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- = Parallel Port Information System =
- = =
- = version 1.45 =
- = =
- = by =
- = =
- = Jay Lowe =
- = Don Schuman =
- = =
- = Parallel Technologies, Inc. =
- = =
- = =
- ======================================================
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- Version 1.45
- 27 Oct 1994
-
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-
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- Reference Sites for Parallel
-
- Compuserve Home: IBMHW forum (go IBMHW)
- Internet Home: netlab2.usu.edu/misc
-
-
-
-
- ======================================================================
- Parallel.Exe, v1.45, 27 Oct 1994 Parallel Technologies, Inc.
- Parallel Port Information Utility 10603 170th Ct NE
- (C) Copyright 1993-1994 Jay Lowe Redmond, WA 98052
-
- This program may be used Lab 206-869-1136
- free of charge subject to the Fax 206-869-1133
- Restricted License Agreement Compuserve 76640,203
- as stated below Internet jaylowe@halcyon.com
- ======================================================================
-
-
- Parallel Port Information System Page 2
- ---------------------------------------------------------------------------
-
- Front Matter
- ------------
-
-
- IMPORTANT: This software is provided AS-IS under a license agreement
- stated below (see SOFTWARE LICENSE AGREEMENT). YOU ARE RESPONSIBLE for
- the safe usage of this program. This requires that you READ THE
- DIRECTIONS if you are going to use the loopback feature for IRQ
- detection. We are informing you of the danger of physically damaging
- your parallel port if you are not CAREFUL AND GENTLE when inserting
- the loopback wire. We strongly recommend that you follow the procedure
- of making a LOOPBACK EXTENSION CABLE as described below. To the best
- of our (extensive) knowledge, there is no electrical danger to
- yourself or to your system or to the parallel port, since parallel
- ports are designed to withstand permanent shorts across any of their
- pins. HOWVER WE DO NOT GUARANTEE AN OF THIS AND CAN ACCEPT NO
- LIABILITY since we cannot control what you or your vendor may do.
-
-
-
- Parallel.Exe, Parallel.Doc, and all of the associated components of
- this utility are copyrighted material and may not be reproduced,
- redistributed, or sold without the express written consent of Parallel
- Technologies, Inc, except as provided by the License Agreement.
-
-
- Some of the terms, names, and/or symbols used in this document are the
- trademarks of the companies which own them.
-
-
- Permission is hereby given for distribution of Parallel on a not-for-
- profit basis. Users may upload and share Parallel, provided it is not
- modified in any way. Vendors may make Parallel available via bulletin
- boards or other electronic forums, but may not distribute Parallel
- with their products without the permission of Parallel Technologies,
- Inc. Shareware vendors and other software distributors may distribute
- Parallel provided they do not charge more than $10 per copy.
-
-
- Support for Parallel and parallel port related issues is available
- only via Compuserve or Internet Email to the addresses given on the
- cover page of this manual.
-
- Parallel Technologies, Inc. does not provide telephone support for
- this program.
-
-
- Parallel Port Information System Page 3
- ---------------------------------------------------------------------------
-
- Acknowledgements
- ----------------
-
- We would like to express our appreciation to the many people and
- organizations who have given of their time and expertise to provide
- information and support for Parallel in various ways. Some of these
- contributors include:
-
- Parallel Port Chipset Vendors:
-
- Intel Corporation
- Standard Microsystems Corporation
- National Semiconductor
- Chips and Technologies
-
- Parallel Port Direct Sales Vendors:
-
- Farpoint Communications
- JAZ Computer Products
- Essential Data, Inc.
-
- Standards Organizations:
-
- Members of the EPP Standards Committee
- Members of the IEEE 1284 Standards Committee
-
- Individuals:
-
- Larry Stein, Farpoint Communications
- Prof. Joe Dupnik, Utah State University
- Don Watson, Compuserve IBMHW Forum Sysop
-
- The users:
-
- who have reported test results, bugs, and feature requests!
-
- And the innumerable hackers who have gone before.
-
-
- My thanks to all of you for your generosity.
-
-
- And if I've left anyone out, my apologies. Please remind me.
-
-
- Parallel Port Information System Page 4
- ---------------------------------------------------------------------------
-
- Table of Contents
- -----------------
-
-
-
- FRONT MATTER 2
-
-
- ACKNOWLEDGEMENTS 3
-
-
- TABLE OF CONTENTS 4
-
-
- WELCOME TO THE PARALLEL PORT INFORMATION UTILITY 7
-
-
- QUICK STARTING PARALLEL 8
-
-
- DETAILED PROGRAM OPERATION 9
-
- How to Prepare Your System for Best Results 9
-
- How to Run Parallel.Exe 9
-
- How to Get Quick Help 9
-
- How to Prevent Scrolling 9
-
- How to Save Parallel's Output 9
-
- How to Avoid the Funny Line Drawing Characters 9
-
- How to get Help with your Parallel Port Questions 10
-
-
- INTERPRETING PARALLEL'S DISPLAY 11
-
- Parallel Port Type 11
- No Port 11
- 4bit ports 12
- 8bit ports 13
- EPP ports 14
- ECP ports 16
-
- IO Address 18
-
- Understanding the IRQ Level 20
-
- Understanding the BIOS Name 22
-
- Understanding the Notes and Comments 24
-
-
- Parallel Port Information System Page 5
- ---------------------------------------------------------------------------
-
- AUTOMATIC IRQ DETECTION 30
-
- Understanding Port Float 30
-
- IRQ detection using the LoopBack Feature 31
-
- TechNote: Making Your Own Loopback Connector 33
-
-
- MISCELLANEOUS TOPICS 34
-
- Technote: Pseudo-Bidirectional Ports, A Special Case 34
-
-
- PARALLEL PORT STANDARDS 35
-
- 4bit and 8bit parallel ports 35
-
- EPP Specification 35
-
- ECP Specification 35
-
- IEEE 1284 Specification 36
-
- Parallel Port Standards Diagram 37
-
-
- PARALLEL PORT BUYER'S GUIDE 38
-
- 4bit parallel ports 38
-
- 8bit parallel ports 38
-
- EPP Parallel Ports 39
-
- ECP Parallel Ports 41
-
- Advanced Parallel Port Chipsets 42
-
-
- VENDOR CONTACT INFORMATION 44
-
-
- TECHNICAL SUPPORT 45
-
-
- ABOUT PARALLEL TECHNOLOGIES, INC. 46
-
- Firsts, Bests, and Mosts 46
-
- Partial List of Parallel Technologies' Developments 46
-
- Parallel Port Developer's Kits 47
- Level One Developer's Kit 47
-
-
- Parallel Port Information System Page 6
- ---------------------------------------------------------------------------
-
- Level Two Developer's Kit 48
- Super IEEE 1284 Developer's Kit 48
-
- DirectNet -- The Parallel Port Networking System 48
-
- Parallel -- the Parallel Port Information Utility 49
-
- OEM Products 49
-
- Development Services 50
-
- Consulting and Training 50
-
-
- SOFTWARE LICENSE AGREEMENT 51
-
-
- Parallel Port Information System Page 7
- ---------------------------------------------------------------------------
-
- Welcome to the Parallel Port Information Utility
- ------------------------------------------------
-
- Parallel is a simple utility which displays the configuration of the
- parallel ports (LPT ports) in your system. Parallel is useful for:
-
- 1. Configuring parallel port software such as Windows printer
- connections, parallel port device drivers, and print spoolers.
-
- 2. Resolving technical support problems with parallel devices,
- including printers and external peripherals such as network
- adapters, portable disks, tape drives, CD-ROMs, floppies, etc.
-
- 3. Configuring your parallel ports for best performance.
-
- 4. Resolving pesky IO address and IRQ contention problems.
-
- 5. Measuring the performance capabilities of your parallel ports.
-
- 6. Learning how your particular system's CMOS configuration
- relates to the actual configuration of your parallel ports.
-
- 7. Making informed decisions when buying parallel ports and
- external parallel port devices.
-
- 8. Getting the best parallel port performance for your dollar.
-
- 9. Experimenting with your parallel port configuration.
-
- 10. Solving problems associated with print spoolers and network
- print capture programs which redirect printer output by
- changing the port mappings kept in the LPT Bios data area.
-
- Now is a good time for you to learn something about parallel ports.
- Parallel ports are becoming increasingly useful due to the recent
- explosion in the popularity of portable and external peripherals.
- New parallel port standards (such as EPP and ECP ) are breaking
- performance barriers and allowing full bus speed operation.
-
- Parallel ports have traditionally been perceived as "printer ports",
- which explains a lot about their idiosyncrasies. In fact, a relatively
- small percentage of parallel ports are actually used for printing. The
- ratio of PCs to printers is usually "many to few" in a group setting,
- and as networking and networked printers become increasingly common
- this trend will increase. In general, PC parallel ports are usually
- available for other purposes ... for portable, external peripherals
- and parallel port networking (Desktop and Personal Area Networking).
-
- There are major performance differences between different types of
- parallel ports and parallel port devices, and these differences are
- becoming of increasing significance to consumers. These applications
- of Parallel are discussed in more detail below. But first let's take a
- quick look at how you run the program itself and interpret the various
- information it displays.
-
-
- Parallel Port Information System Page 8
- ---------------------------------------------------------------------------
-
- Quick Starting Parallel
- -----------------------
-
- Parallel operates by testing each of the standard addresses in your
- system where parallel ports might be found and gathering a broad
- assortment of useful information about the specific port behavior.
- Parallel tests the ports and then produces a compact display which
- is convenient and easy to read. You may need to refer to these
- instructions or the built-in reference screen a few times until you
- learn what the various columns of information mean.
-
- How to use Parallel:
-
- Step 1 => Disconnect any attached parallel port peripherals such
- as printers, LAN adapters, disks, CDROMs, etc
-
- Step 2 => Run PARALLEL from the DOS command line (not in Windows)
-
- Step 3 => Read the display as described below.
-
- Parallel will display five columns of information containing one or
- more lines about each port. The columns are:
-
- Port Type The parallel port's IO capabilities. Types are:
-
- No Port -- No port is exists at the address
- 4 bit -- A "unidirectional" port
- 8 bit -- A "bidirectional" port
- EPP -- An Enhanced Parallel Port
- ECP -- An Extended Capabilities Port
-
- Address IO Base Address of the port (3BC, 378, 278)
-
- IRQ Interrupt level associated with the port (5 or 7)
-
- BIOS Name Logical device name of the port (LPT1, LPT2, LPT3)
-
- Notes A wide assortment of comments, warnings, and
- miscellaneous additional information
-
- Port On a single line, after the columnar display,
- Strangeness Parallel ports a magic number called the
- Factor. `Port Strangeness Factor'.
-
- This is simply the total number of strange or unusual properties that
- Parallel has found when examining your configuration. If your ports
- are considered strange by Parallel, you might want to take some action
- to correct the situtation, or at least appreciate the peculiarity.
-
- The Port Strangeness is not reported if your configuration is boring.
-
- Detailed procedures for using Parallel are given in the next section.
-
-
- Parallel Port Information System Page 9
- ---------------------------------------------------------------------------
-
- Detailed Program Operation
- --------------------------
-
- How to Prepare Your System for Best Results
- -------------------------------------------
-
- Before running Parallel, temporarily remove all parallel port
- devices and software to establish a baseline configuration.
-
- Temporarily disconnect printers and other parallel port devices
- such as disks, network adapters, tape drives, etc, and disable any
- special parallel port software you may have running, like print
- spoolers or parallel port device drivers for external devices.
-
- The interaction of Parallel with external devices is discussed in
- some detail later on, and you may find that disconnecting these
- devices is not necessary in your configuration.
-
- How to Run Parallel.Exe
- -----------------------
-
- Type PARALLEL at the DOS command line.
-
- Parallel will display the parallel port type, IO address, IRQ
- level, BIOS names, and an assortment of informative notes about
- your parallel ports. Running Parallel in a Windows DOS box
- generally provides useless results.
-
- How to Get Quick Help
- ---------------------
-
- PARALLEL ? ; displays the a reminder screen
-
- How to Prevent Scrolling
- ------------------------
-
- If, perchance, the display scrolls off the screen, which might
- happen if Parallel is reporting extensive notes about interesting
- conditions on your ports, then use the MORE command as follows:
-
- PARALLEL | MORE ; pauses the output every screen
-
- How to Save Parallel's Output
- -----------------------------
-
- Use DOS redirection to write Parallel's display to a file:
-
- PARALLEL > filename ; redirects output to a file
-
- How to Avoid the Funny Line Drawing Characters
- ----------------------------------------------
-
- Sorry, you can't. We plan to add a switch to omit or replace the
- linedrawing characters for more convenient display via email, etc.
-
-
- Parallel Port Information System Page 10
- ---------------------------------------------------------------------------
-
-
- How to get Help with your Parallel Port Questions
- -------------------------------------------------
-
- 1. Contact your vendor.
-
- Your vendor has a responsibility to support you in using
- their products.
-
- If you have a problem with a parallel port device, your
- vendor may already know a successful resolution.
-
- Some vendors maintain BBS systems or Compuserve forums
- on which may occasionally be found useful information,
- utilities, and driver software upgrades.
-
- Many vendors of parallel port peripherals offer very
- good technical support IF YOU GIVE THEM A CHANCE ... or
- several chances! Don't hesitate to be persistant.
-
- If you have a problem configuring a PC parallel port,
- your vendor may already have a fix ready for you. This
- may consist of a utility program, a BIOS upgrade, or a
- manual procedure for configuring the port. Since PC
- vendors use a bizarre array of different methods for
- parallel port configuration, your best bet is really
- the vendor themselves. Alas, however, some PC vendors
- are completely clueless about parallel ports, although
- this situation is improving rapidly.
-
- Give your vendor a chance to resolve the problem. They are
- sometimes the most responsive source of assistance, AND THEY
- NEED YOUR INPUT. Let them know what you want, and what you
- are doing -- it helps them adjust their plans and priorities.
- If you are not getting the proper assistance, call your
- vendor and let the product manager know about the situation.
-
- Think of it as your contribution to overall product quality!
-
- And if Parallel doesn't detect your ports tell your vendor to
- (a) get a copy of Parallel and (b) help us detect their port!
-
- 2. Post your question in the IBMHW forum on Compuserve or in the
- IBM PC Hardware newsgroup on the Internet.
-
- Quite a few technical gurus read these forums and they tend
- to be generous in giving you the benefit of their experience.
-
- 3. Email to CIS ID 76640,203 or jaylowe@halcyon.com.
-
- We can't promise immediate service (or indeed any service at
- all!) but we try to do our best. Please understand that we
- get quite a few random technical inquiries and have to fit
- them around our development schedule.
-
-
- Parallel Port Information System Page 11
- ---------------------------------------------------------------------------
-
- Interpreting Parallel's Display
- -------------------------------
-
-
- Parallel Port Type
- ------------------
-
- Parallel reports the port type as 4bit, 8bit, EPP, ECP or No Port.
-
- No Port
- -------
- No port was found at the given IO Address. This is a
- normal result if no parallel port is installed at the
- given address.
-
- Parallel tests all the base addresses at which parallel
- ports are commonly found and displays at least one line
- of information about each base address, even if there
- is no port installed at that address.
-
- Parallel uses a rather more robust technique for
- detecting a port than is used in any of the BIOSes we
- have seen. This means that Parallel can detect ports
- which fail the BIOS boot-time tests. Parallel uses a
- rotating bit test and assumes the port exists if any of
- the bits at the port location respond correctly.
-
- Parallel is also starting to detect specific advanced
- parallel port chipsets. Intel and SMC detection is
- present in this release and National and C&T detection
- will be included in the next release.
-
- False Positives. Parallel can be fooled into thinking
- that a port is present when it is not (false positive)
- only if there is some other device which behaves like a
- parallel port located at the address being tested. We
- have only seen this on one system, an off-shore 286
- laptop which had several other design problems as well.
-
- False Negatives. There is one way in which Parallel
- can be fooled into thinking that a port does not exist
- (false negative). If an active device is connected to
- the data lines and is providing enough power to
- "overdrive" the port, then the port existance test will
- fail because the incoming data from the device will
- spoof the readback test. We have only seen Parallel
- produce false negatives when an external device is
- actively driving the port's inputs or when the Loopback
- connector is incorrectly installed. By the way, in this
- case, the PC's BIOS will also fail to detect the port.
- Remember, Parallel works best when you disconnect any
- external parallel port devices or cables.
-
-
- Parallel Port Information System Page 12
- ---------------------------------------------------------------------------
-
- 4bit ports
- ----------
-
- The port can do 8bit byte output and 4bit nibble input.
-
- These ports are often called "unidirectional", and are
- most commonly found on desktop bus cards (also called
- IO expansion cards, serial/parallel cards, or even 2S+P
- cards) and older laptops. This is still the most common
- type of port, especially on desktop systems.
-
- HOW FAST: 4bit ports are capable of effective transfer rates of
- about 40-60 KBytes/sec (KBPS) in typical devices and
- can be pushed upwards of 140 KBytes/sec with certain
- design tricks. The port speed is also affected by
- electrical characteristics of the noise suppression
- circuitry. A few ports have completely ridiculous
- arrangements of noise suppression circuits which slow
- them down quite dramatically and can prevent their
- correct functioning with parallel port peripherals.
-
- TECH NOTE: The sample transfer rates given here reflect the actual
- performance of parallel port network adapters, disks,
- etc. The raw transfer rate of the port itself is higher
- but since most parallel devices use software strobing
- to access data , the effective transfer rate is
- dependent on the quality of the software supplied with
- the device. Due to the recent explosion of parallel
- port peripherals entering the market, there is an
- extreme degree of variability in the quality and
- performance of these devices and their drivers.
-
- WHERE FOUND: 4bit ports are found on about 50% of all systems and
- about 75% or more of desktop systems prior to 1993.
- Systems built after 1993 are more likely to have more
- capable parallel ports such as 8bit, EPP, or ECP.
-
- TECH NOTE: Many new systems, especially laptops, have parallel
- ports whose mode can be selected via a CMOS setup
- procedure. Often these system default to a 4bit port
- type even if more port capabilities are present.
-
- We do not recommend 4bit ports; 8bit ports are better.
-
- TECH NOTE: There is a class of "semi-bidirectional" parallel ports
- which appear to the PC to be 4bit ports, but actually
- have 8bit capability when they are connected to
- external devices with strong drivers. These include the
- original PC/AT parallel port. Parallel will report such
- ports as 4bit ports but they may actually function as
- 8bit ports with better parallel port peripherals which
- are especially designed to use such port as 8bit.
-
-
- Parallel Port Information System Page 13
- ---------------------------------------------------------------------------
-
- It is actually possible to identify this type of port
- using a side-effect of Parallel's loopback test. See
- the special section below on Semi-Bidirectional ports.
-
- 8bit ports
- ----------
-
- These ports can do both 8bit input and output.
-
- These ports are sometimes called "bidirectional ports",
- but that term is often misused by some vendors to refer
- to 4bit ports as well. Most newer laptops have 8bit
- capability although it may need to be enabled with the
- laptop's vendor-specific CMOS setup function. This is
- discussed below. A relatively smaller percentage of LPT
- bus cards have 8bit capability which sometimes must be
- enabled with a hardware jumper on the board itself.
-
- True 8bit ports are preferable to 4bit ports because
- they are considerably faster when used with external
- devices that take advantage of the 8BIT capability.
-
- HOW FAST: 8bit ports are capable of speeds ranging from 80-300
- Kbytes/second, again depending on the speed of the
- attached device, the quality of the driver software,
- and on the port's electrical characteristics.
-
- WHERE FOUND: 8bit ports are found on about 25% of desktops, about
- 50% of laptops, and 90% of laptops built since 1991.
-
- CAVEAT EMPTOR: A number of vendors claim "bidirectional" capability
- for their parallel ports when they are actually mere
- 4bit ports. When buying a parallel port expansion card,
- or an entire system, you might want to use Parallel to
- find out the REAL capabilities of the port. Be aware
- that a vendor's general reputation for quality may not
- translate into good parallel ports. There are examples
- of well-known vendors making false claims for their
- parallel ports... sometimes, it appears, simply because
- they don't understand them... the claims or the ports.
-
- We are not going to pan anyone's "bidirectional"
- parallel ports specifically, but be warned that the use
- of terms like "bidirectional" or "PS/2 compatible" may
- have nothing to do with the port's actual capability.
-
- Some vendors even refer to 8bit ports as "enhanced",
- which is totally misleading and creates no end of user
- confusion. Make sure exactly what you are getting.
-
- The moral of the story ... use Parallel to test ports
- to determine their real I/O behavior and compatibility.
-
-
- Parallel Port Information System Page 14
- ---------------------------------------------------------------------------
-
- Remember that if Parallel can't detect the port, or
- reliably report it's actual behavior, then chances are
- good that other software won't be able to either!
-
- EPP ports
- ---------
-
- Can do both 8bit input and output at ISA bus speeds.
-
- This type of port is defined by the EPP 1.7 standard,
- by the actual behavior if the Intel 360SL I/O chip, and
- also by the IEEE 1284 standard (which is substantially
- incompatible with the EPP 1.7 standard - more below).
-
- HOW FAST: These ports are as fast as 8bit bus cards and can
- achieve transfer rates of upwards of 1 Mbyte/sec. For
- example, our EPP-capable external SCSI disk is faster
- on a popular SL laptop than it's own internal drive.
-
- EPP ports are supposed to conform to a well defined
- electrical standard and many of them actually do so.
- However, if you are buying a laptop and want to be sure
- of using fast EPP-capable external peripherals, then
- you should definitely arrange to try before you buy.
-
- HISTORY: EPP ports came about as a joint effort involving
- Zenith, Intel, and Xircom. After the introduction of
- the EPP port capability in the Intel 360SL I/O chip,
- many manufacturers began providing this feature on
- their SL-based laptops. An EPP Standards Committee was
- formed which standardized the behavior of the Intel SL
- EPP port as the EPP 1.7 standard ... and life was good.
-
- Then the EPP standards committee merged with the IEEE
- 1284 committee which was itself struggling to specify
- new parallel port type(s) with a predominant focus on
- fast and bi-directional communication for printers.
- Parallel port peripherals other than printers were
- considered strange beasts and received extremely short
- shrift in the 1284 deliberations, to the point that the
- 1284 specification does not really embody a long term
- vision of the parallel port as a high-speed external
- pathway for interfacing various peripherals to the PC.
-
- Also, the 1284 committee did not like the details of
- how the signalling occurred between the PC and the
- attached device in the EPP 1.7 spec, and agreed to
- include EPP within the scope of IEEE 1284 only if the
- EPP standard was changed to correspond to the rules for
- 1284 signalling. Hence the IEEE 1284 EPP spec, which
- is incompatible with the original EPP 1.7 spec.
-
- As a result, there are actually TWO standards for EPP
- signalling, the original 1.7 specification (embodied in
-
-
- Parallel Port Information System Page 15
- ---------------------------------------------------------------------------
-
- hundreds of thousands of SL laptops) and the IEEE 1284
- EPP specification (embodied in a new generation of IEEE
- compatible parallel ports which support multiple modes
- of parallel port operation - see below). A typical IEEE
- 1284 style parallel port supports a combination of
- Compatible (4bit and/or 8bit), EPP (version 1.7 and/or
- 1284) and/or ECP (which we visit in the next section).
-
- EPP BIOS: To make matters more complicated, the EPP Standards
- Committee began work on an EPP BIOS spec quite some
- time ago but the specification is still not adopted
- either formally by the (now) IEEE 1284 Committee or by
- any significant numbers of vendors. It is uncertain
- whether such a BIOS will ever be widely supported, and
- in any case, it will be too little - too late, because
- developers will still be required to support the
- existing defacto standards for non-BIOS interfaces as
- well as the hypothetical new BIOS standard. This
- reduces the EPP BIOS's usefulness; instead of being a
- global standard, it becomes just another special case.
-
- If this seems complicated to you, then congratulations,
- you have successfully evaluated the situation!
-
- CAVEAT EMPTOR: Therefore, when buying a system or external peripheral
- which has high-speed EPP capability, it is crucial to
- determine whether the system or device supports EPP 1.7
- or EPP 1284 or both. See the Buyer's Guide section for
- more information on this subject.
-
- Xircom was active in creating and defining the EPP 1.7
- standard, and since their EPP-capable network adapters
- are fairly common, it's worth mentioning that these
- adapters can be used as a practical benchmark for the
- goodness of a EPP 1.7 port. Crude but effective.
-
- EPP ports are most often found on laptops using the
- Intel 386SL chipset with the 360SL I/O support chip or
- a register-compatible parallel port implmentation. You
- can usually identify these laptops by the 'SL' suffix
- in their name, HOWEVER this is not a hard and fast
- rule, since there are non-SL systems with EPP ports as
- well as SL systems which (in our tests) have non-
- functioning or sub-standard EPP ports. Other vendors
- offer add-in EPP cards for the ISA bus.
-
- The Future: Standard Microsystems Corp., National Semiconductor,
- and Chips and Technologies have released multifunction
- chipsets with both EPP and ECP capability, so users can
- expect to see fast ports become available on a wider
- range of systems. Other such chipsets are on the way.
-
- This new generation of chipsets, combined with the IEEE
- 1284 standard, provides another window of opportunity
-
-
- Parallel Port Information System Page 16
- ---------------------------------------------------------------------------
-
- for a comprehensive parallel port technology solution.
- It remains to be seen if parallel port hardware and
- software vendors will produce a cohesive response, or
- if parallel ports will remain the PC's prodigal child.
-
- ECP ports
- ---------
-
- Can do both 8bit input and output at bus speeds.
-
- The specification for this port type was jointly
- developed by Microsoft and Hewlett-Packard.
-
- ECP ports are distinguished by having DMA capability,
- on-board FIFOs at least 16 bytes deep (too small), some
- hardware data compression capability, and are generally
- more featureful than other ports.
-
- The MS/HP ECP port specification defines the ISA bus
- registers by which the PC software can read and write
- data at high speed to an attached device.
-
- The MS/HP ECP port specification (what's inside the PC)
- is related to the IEEE 1284 specification (what happens
- on the wires outside the PC in various modes).
-
- HOW FAST: These ports are as fast as 8bit bus cards and can
- achieve transfer rates upwards of 1 Mbyte/sec and
- faster on PCs whose buses will support it. The design
- is capable of faster transfer rates in the future.
-
- TECH NOTE: ECP port specification defines an ECR control register
- with port mode configuration bits which may be used to
- place the ECP port into several different submodes.
-
- The ECP specification defines a multimodal port which
- can support backward compatible and enhanced modes of
- operation.
-
- My goodness, this is starting to look like an excellent
- solution to the proliferation of incompatible parallel
- port standards. A standard port with multiple modes!
-
- Alas, the ECP port specification does not define an EPP
- mode, so vendors have chosen various ways of providing
- an EPP capability within the framework of the ECP port
- specification. Let's look at how this works.
-
- SMC, for example, uses a reserved bit of the ECR
- register to place the port into EPP 1284 mode on their
- 66xQPF chip (see Parallel Port Buyer's Guide). The
- 66xQPF chip, used on the Intel Pentium motherboards,
- does not support EPP 1.7, which means that the large
- installed base of parallel port network adapters,
-
-
- Parallel Port Information System Page 17
- ---------------------------------------------------------------------------
-
- external disks, SCSI adapters, etc generally don't work
- on such systems. When SMC figured this out, they
- announced the 66xGT revision of the chip, which has TWO
- EPP modes, 1.7 and 1284, as well as various bug fixes.
-
- In addition, the SMC chip implements a TWO level
- approach for controlling parallel port configuration.
- The 66x contains configuration registers which ENABLE
- the port to be in Standard, EPP-only, ECP-only, or EPP-
- ECP modes. If the port is in ECP or EPP-ECP modes, then
- the actual submode is SELECTED according to the ECP
- spec by using the ECR register which appears on the bus
- only when the chip is ENABLED for ECP or EPP-ECP.
-
- To make matters even more complicated, other vendors
- have taken other approaches to shoehorning EPP into the
- framework of the ECP specification.
-
- STANDARDS: Note that while both the EPP and ECP parallel port
- specifications establish how the port operates within
- the PC when it is enabled, the specs do not describe
- how the enablement occurs - that is left to vendors.
-
- For example, the EPP 1.7 specification defines the
- various I/O registers of the EPP port, but does not
- define how to detect such a port or enable it.
-
- Similarly, the ECP port specification defines the port
- I/O registers and some of the configuration processes,
- but does not define exactly how such ports are enabled,
- this is a constant problem with inadequate standards.
-
- Therefore it is possible for vendor ABC's excellent EPP
- 1.7 (or ECP, etc) device to fail to operate on vendor
- XYZ's system because XYZ implemented the port in a way
- that ABC does not recognize (yet). Parallel port device
- vendors are constantly challenged by the appearance of
- new types of ports - and the better vendors frequently
- have software upgrades which support specific ports.
-
- Existing parallel port standards have missed the mark.
-
- they do not qualify as fully conceived response to the
- overall requirement for speed, vendor flexibility, and
- ease of use in the PC environment. These standards have
- focused on bringing short-term capabilities to market
- rather than on providing a comprehensive, universal
- solution to the end user.
-
- In the Buyer's Guide section, we will attempt to throw
- some light on your practical options when shopping for
- a system with fast parallel ports. The Parallel Port
- Standards section reviews the various parallel port
- standards, de facto and de jure.
-
-
- Parallel Port Information System Page 18
- ---------------------------------------------------------------------------
-
-
- IO Address
- ----------
-
- Also called the "base address" the port. It will almost always be
- 3BC, 378, or 278 hex. A very rare subset of parallel ports may
- support additional addresses such as 280, 290, etc.
-
- The IO address specifies the port's location on the PC's IO bus.
-
- Normally the first port is configured to 3BC, the second to 378,
- etc, however ports can be assigned to any of these three addresses.
-
- On bus cards, the IO address is usually set by a arrangement of
- jumpers unique to the particular board. You will need a manual or
- the ability to read PC board traces (gacck!). These jumpers are
- usually arranged to allow you to select one of three addresses.
-
- Sometimes these addresses are called by the "logical device names"
- of LPT1, LPT2, and LPT3, although this practice is quite misleading
- (see BIOS discussion below).
-
- Some boards offer a more limited selection of configurations,
- usually 378 and 278, and a few are actually hardwired to a specific
- address. Vendors do this to save a little money and to eliminate
- the chance of creating an address collision with the "standard"
- address of 3BC. Because of the increasing number of clones which
- are assembled from various components, we often see systems with
- one LPT card, configured to address 378. In fact, a fair number of
- systems are shipped with this 378 default configuration.
-
- A slightly interesting result we've seen in several desktops spins
- off when someone adds a second LPT card to a system which already
- has a LPT at 378, IRQ 7. Sometimes they naively reason that since
- 378 is taken they can use 3BC and slap in the card without checking
- the IRQ level. This creates a configuration of 3BC and 378 both
- using IRQ 7, a situation which can lead to intermittent crashes
- when using interrupt-driven parallel port software.
-
- By the way, some systems have parallel ports and com ports built
- onto the motherboard itself and, in this case, the configuration
- jumpers will be found on the motherboard or, as in the case of more
- recent systems, in the CMOS SETUP utility.
-
- The new generation of ECP-capable parallel ports typically
- implement software selectable modes, base addresses, and IRQs.
-
- If you have one of these new parallel ports, you will require
- appropriate software in order to configure your port. This may
- exist within the CMOS setup function or may exist as a separate
- utility. When you buy a system or an add-in card which has
- advanced parallel port functionality MAKE SURE YOU GET THE SOFTWARE
- which allows you to enable it. Some vendors include it, some don't.
-
-
- Parallel Port Information System Page 19
- ---------------------------------------------------------------------------
-
- Be aware of the distinction between configuration software which
- allows you to control the configuration of your port, and device-
- specific driver software which uses the port.
-
- Notice that there are three commonly used IO Addresses (3BC, 378,
- 278) and two available interrupt levels (IRQ 7 and IRQ 5). This
- means that if you have three LPT cards in a system, two of them
- will probably be configured to share a hardware interrupt level.
- This is hardwarily permissible, and generally doesn't create any
- problems since most DOS and Windows software doesn't ENABLE
- interrupts for printing anyway. However, if you are using LPT
- software like an interrupt-driven print spooler or interrupt-driven
- LPT devices like external hard disks, external network adapters,
- and so forth, then you have to be sure that either (1) the ports
- are not using the same interrupt level, or (2) both the ports and
- the software are capable of "interrupt sharing".
-
- When adding or configuring LPT cards, we suggest using 3BC, IRQ 7
- for the first card; 378, IRQ 5 for the second card; and 278, no IRQ
- for the third card. This gives you two interrupt-capable LPT ports,
- and one port (at 278) which you should use only for non-interrupt
- driven usage, like the status-driven spooling provided by DOS.
-
- You should only configure your system to share interrupts when you
- are (1) absolutely sure that they will not be simultaneously
- enabled, and (2) when you have totally run out of other options.
-
- Also, you should know that many sound cards, like the SoundBlaster,
- arbitrarily use IRQ5 by default. This was a bad design decision,
- especially so since the SoundBlaster's implementation of interrupts
- creates a serious conflict when sharing the interrupt with other
- devices, but we are stuck with it. If you are using a sound card
- on IRQ 5, then you should definitely AVOID ENABLING that level on
- any of your parallel ports.
-
- Armed with this understanding and the Parallel Utility, you are
- equipped to select a configuration which works for you.
-
- HOW TO: The IO ADDRESS is a standard parameter in network
- configuration files where it takes on different names
- to confuse innocent users. (Base, Port, etc).
-
- Some simple-minded parallel port peripherals (ones
- without auto-configuring capability) require that you
- specify the IO address, IRQ level, and sometimes the
- Port Type in a vendor-specific way. Parallel provides
- you with this information.
-
- HOW TO: Resolving IO Address conflicts is usually fairly
- simple, since it is rare to find a device which uses
- the standard parallel port addresses.
-
- A good procedure for eliminating potential IO address
- conflicts when installing parallel port add-in boards
-
-
- Parallel Port Information System Page 20
- ---------------------------------------------------------------------------
-
- is to remove all the boards, install one, use Parallel
- to see what address it finds, install the next, and so
- forth. If Parallel finds each board at a separate
- addresses as you install them, then you can be sure of
- your configuration.
-
- Understanding the IRQ Level
- ---------------------------
-
- This is the hardware interrupt level assigned to the port. It will
- almost always be either 7 or 5. Only a few specific parallel ports
- support IRQ levels other than 7 or 5.
-
- Parallel displays:
-
- "?" when it cannot detect the IRQ level of the port and
- "-" when it knows the the port doesn't exist.
-
- Parallel needs an external loopback connector to automatically
- detect the IRQ. With appropriate precautions (described in horrible
- and excruciating detail below) you can use a simple paperclip as a
- loopback connector.
-
- Normally IRQ 7 is assigned to the first port and IRQ 5 is assigned
- to the second port. However, due to the explosion of clones
- assembled from disparate parts, it is not uncommon to see systems
- with one LPT port located at 378 with an IRQ of 7 or 5. This is
- because clones are often assembled using offshore add-in LPT cards
- which are shipped configured to operate as a second LPT card.
-
- This is a good time to point out that there are few hard and fast
- rules when it comes to parallel port configuration. Ports can be
- located at any one of the three standard base address and can use
- either of the IRQ levels. If you are developing parallel port
- software, you should auto-detect the actual configuration rather
- than assume any standard usage.
-
- We offer libraries and source code for this purpose. Here at
- Parallel Technologies, we test our software using many strange
- configurations and delight in adding idiosyncratic ports to our
- extensive collection.
-
- The most common idiosyncrasy of port IRQ is IRQ inversion. The PC
- standard calls for interrupts to be generated on 0->1 transitions
- of the interrupt line. A small percentage of parallel ports
- generate their interrupts on 1->0 transitions. Ports with inverted
- IRQ can fail to operate with some interrupt software, particularly
- certain external network adapters, disks, and so forth. Parallel
- identifies these ports with a note "IRQ style is INVERTED".
-
- Some parallel ports have non-functioning IRQ lines. They are simply
- not capable of generating interrupts. Only a very few pieces of
- software are capable of dealing with these ports by using a polled
-
-
- Parallel Port Information System Page 21
- ---------------------------------------------------------------------------
-
- mode of operation. It is sometimes possible to repair such systems
- by jumpering the interrupt enable line to the parallel port chip.
-
- In the case of an add-in board with broken IRQ capability, check to
- be sure the IRQ jumper, if any, has not gone missing somehow.
-
- On ISA cards (bus cards in ISA slots) the interrupt level is
- usually set with jumpers on the board - these jumpers are different
- for every card so you need to hunt around for the manual in order
- to change them. If you're lucky there will be readable labels on
- the card itself.
-
- On laptops and an increasing number of desktops, the IRQ level can
- usually be set using the vendor's CMOS configuration (setup)
- program. Sometimes these CMOS setup programs are built into the
- ROM; sometimes they exist as separate programs or as part of the
- vendor's diagnostic program(s). Refer to your manual to find out
- how to enter the CMOS setup mode. BE CAREFUL when using the CMOS
- setup, since it gives you access to parameters that can disable
- your system if wrongly changed. KNOW WHAT YOU ARE DOING. DON'T
- CHANGE ANYTHING YOU DON'T FULLY UNDERSTAND. WRITE DOWN THE INITIAL
- VALUES OF ANY SETTINGS YOU CHANGE. ASK YOUR VENDOR FOR HELP.
-
-
- ******************
- * IMPORTANT NOTE *
- ******************
-
- Misuse of your system's CMOS setup program can prevent your system
- from operating correctly, or in some cases, from operating at all!
-
- Be sure you know what you are doing; read your user's manual or get
- qualified help if you have any doubts.
-
- Another strange feature of these software configurable ports is
- that they often have very peculiar ideas about nomenclature. Often
- these CMOS setup programs use vendor specific "magic code words" to
- select various parallel port configurations, and these magic words
- can have non-obvious effects. Sometimes the vendor's manuals don't
- even provide a secret decoder ring to explain what their magic
- words really mean in terms of IO Address, IRQ, and Port Type.
-
- Parallel will be useful for determining the actual effect of the
- CMOS setup choices on your system.
-
- For example, on my Dell NL25 laptop, 4bit mode is called "Normal"
- and 8bit is called "Enhanced" and there is no choice at all for the
- real Enhanced Parallel Port (the SL's EPP port). So someone might
- obviously think they have enabled EPP by choosing "Enhanced".
- Futhermore, the IRQ level cannot be set directly, but rather is set
- as a by-product of selecting combinations of the IO address and the
- Port Type. Most of the choices on my Dell yield IRQ 7, but one
- lonely choice - LPT1, 278, Normal mode results in IRQ 5. It makes a
- bizarre sort of sense when you are experienced with parallel ports,
-
-
- Parallel Port Information System Page 22
- ---------------------------------------------------------------------------
-
- but is likely to be confusing to the Average User (if we ever find
- him, or her).
-
- The Dell is hardly alone in it's strange naming conventions ...
- most PCs have confusing, misleading, or incomplete labels and
- controls in their CMOS setup programs. This sort of indirect
- control in very common in CMOS setups and creates a lot of tech
- support calls from frustrated users.
-
- In addition, most SL laptops don't have the capability to enable
- their EPP ports from CMOS. Usually you need to run a separate
- vendor-supplied BIOS extension to enable EPP capability. These take
- the form of a tiny TSR which adds INT 17h BIOS extensions for
- controlling the EPP port, and handles command line arguments for
- enabling and disabling EPP. An interesting sidelight of switching
- into EPP mode can be that your port IO address may change on the
- fly. The Intel EPP hardware allows EPP ports to be configured at IO
- Addresses 378 and 278. So if you have set your port address to 3BC
- (with CMOS for example) and then switch into EPP mode, your port
- will appear to have moved.
-
- Parallel will come in handy in trying to make sense of what your
- system's CMOS settings are actually doing to your parallel ports.
-
- Understanding the BIOS Name
- ---------------------------
-
- This is the "human-readable" (hah!) name which you use to refer to
- the port when using DOS commands, Windows picklists, and so forth.
- It will be one of the following: LPT1, LPT2, LPT3. LPT4 is
- extremely rare and Parallel currently ignores it.
-
- The port address is NOT the same as the BIOS name for the port. For
- example, LPT1 can refer to a port at any address: 3BC, 378, or 278.
-
- So how does the BIOS associate the LPT names with the actual ports?
-
- It works like this ...
-
- Whenever your system boots, the BIOS goes out and tries to write
- and read back data from locations 3BC, 378, and 278. If it can read
- back what it writes, then the BIOS decides that a parallel port is
- there and adds the IO address to a LPT table in the "Bios Data
- Area". This table is four words located at memory location 40:8.
-
- A command like "copy foo.txt lpt2:" really means "copy the file
- foo.txt to the second printer that BIOS knows about" and DOS uses a
- software interrupt, INT 17h, to do just that. INT 17h looks in the
- Bios Data area to find out the IO address of the "second printer
- port", which can be any of the IO addresses - 3BC, 378, or 278.
-
- The result is that LPT1 refers to the first port BIOS finds at boot
- time, wherever it may be. So "LPT1" means "the first port found in
-
-
- Parallel Port Information System Page 23
- ---------------------------------------------------------------------------
-
- the address order", not necessarily 3BC, 378, or 278 specifically.
- Some BIOSes have unique methods for finding their LPT ports.
-
- When you see LPT1, LPT2, or LPT3 used to refer to port locations,
- be alert for possible misleading information. Some well-known
- vendor's manuals use LPT1 to refer to 378 and LPT2 to refer to 278,
- etc, an entirely spurious practice which has confused many users.
-
- It is possible for some parallel port software to set the port into
- an IO mode that causes it to fail the simple BIOS test and seem to
- "disappear" from your system even after a soft boot (CTRL-ALT-DEL).
-
- Parallel has a better port detection test, and can usually find
- such ports. A hard reset (a power-off reset) will clear the port.
- Parallel ports are not completely trivial devices; they have a
- number of states that can affect their operation. So if you are
- having a parallel port problem, one of the first things to do is a
- power-off reset.
-
- Another factor here is that various programs can fiddle with the
- LPT table in order to rearrange how the names relate to the ports
- or to accomplish other effects like network print redirection.
-
- The utility SWAPPRT, for example, can be used to swap LPTx with
- LPTy which it does by moving the entries in the LPT table.
-
- There are variations of this redirection theme. Network print
- capture functions (such as those founf in Netware and so forth) put
- special values in the LPT BIOS table to mark that the port is not a
- physical port but rather is a `` virtual port'' which is actually
- served by a software function, usually redirection of INT 17.
-
- Some parallel port devices with passthrough printing ports also use
- this technique to intercept the output of programs which print
- using the INT 17 function call.
-
- If Parallel does not display a BIOS name for a port, that means the
- IO Address for that LPT position has been replaced with a value
- that does not match a valid hardware port. This can occur when some
- other parallel port software has grabbed possesion of the port by
- placing a "magic number" in the BIOS LPT Table.
-
- Remember, the BIOS decides how LPT symbolic names are mapped onto
- physical port addresses, generally by a test a boot time, not the
- vendor's manual, or the jumpers, or the CMOS settings.
-
-
- Parallel Port Information System Page 24
- ---------------------------------------------------------------------------
-
-
-
- Understanding the Notes and Comments
- ------------------------------------
-
- The "Notes" field of the display will contain various comments,
- depending on what Parallel has detected. Each note may be followed
- by one or more comments giving further information or directions.
- These secondary comments are indented one space under their note.
-
- "Port is an XYZZY chip"
-
- Parallel is reporting the specific chipset used to
- implement the parallel port at that address. Some
- vendors may design completely compatible chipsets
- (thank you) which spoof the specific chip detection.
-
- Parallel may also report additional information about
- the current setting of the chipset.
-
- For example, in the case of an SMC 66x chip that is
- enabled for EPP-ECP mode and which currently has the
- Compatible submode of ECP selected (whew!), Parallel
- will report an ECP port with a Note that the port is
- currently in 4bit mode.
-
- "No port found at this address"
-
- No parallel port is installed at this IO Address.
-
- This is a normal result if no port in installed there.
-
- However, it is possible that something is connected to
- the parallel port and is overdriving the port's inputs,
- which prevents the software readback test from working.
-
- Be sure you have disconnected all external devices.
-
- "Need loopback to determine IRQ"
-
- The port exists, but does not respond to attempts to
- generate IRQs. This is because a loopback connector is
- required for IRQ detection in most cases.
-
- "Port IRQs are not functioning"
-
- This is pretty bad. It means that the loopback
- connector is present and working correctly, but
- Parallel still can't generate any interrupts.
- Technically it means that transitions in the ACK line
- are not causing interrupts through the PC's interrupt
- controller.
-
-
- Parallel Port Information System Page 25
- ---------------------------------------------------------------------------
-
- In practice, it means that interrupt-driven devices and
- software won't work, unless they have polling support.
-
- Possible reasons for failing the IRQ test include:
-
- 1. The port's interrupt capability is disabled
-
- Check your CMOS configuration and/or the hardware
- jumpers on the parallel port board(s) to be sure
- that the interrupt is enabled. The function of
- CMOS parameters and/or hardware jumpers varies
- from system to system, so check your manual or
- contact your vendor if you have problems enabling
- the port's interrupt line.
-
- Note that most CMOS and jumper arrangements
- combine enabling the IRQ with selecting the level,
- ie, "enable IRQ5" or "enable IRQ7". Installing the
- jumper may combine selecting a level and enabling
- IRQ. Removing the jumper generally disables IRQ.
-
- 2. The port does not have IRQ capability
-
- Most ports DO have interrupt capability, but a
- small percentage of older systems(at a guess %1 to
- %5) do not. More laptops lack interrupts than add-
- in cards. Add-in cards without IRQ are rare. Most
- reports of non-functional parallel port IRQs in
- desktop systems can be tracked to configuration
- problems which create interrupt conflicts (see #3)
- which effectively disable IRQ.
-
- 3. There is an IRQ conflict with another device
-
- It is possible that another device in your system
- is preventing the parallel port IRQs from
- functioning. For example, in IBM-PCs and XTs, the
- disk controller may use IRQ 5 and prevent parallel
- ports configured to IRQ5 from creating interrupts.
-
- Sound cards frequently use IRQ5 and are likely
- candidates for creating such IRQ conflicts.
-
- To isolate this problem, remove all boards from
- your system which are not required to perform the
- test. In other words, strip down to just the
- parallel port, floppy controller and video, and
- repeat the test.
-
- If possible, configure the parallel port to IRQ7.
- If the port can use IRQ7 interrupts, but not IRQ5
- interrupts, then an interrupt conflict is likely.
-
- "IRQ determined by loopback"
-
-
- Parallel Port Information System Page 26
- ---------------------------------------------------------------------------
-
-
- The loopback was detected, is operating correctly,
- and the port's IRQs are functioning correctly.
- The IRQ level found is given in the IRQ column.
-
- "IRQ estimated by port float"
-
- No loopback connector was detected, but the port
- is generating IRQs anyway. This probably means
- that the port is connected to an inactive
- (unpowered) external device. Treat IRQs determined
- in this way with some skepticism; better to
- disconnect the device and use a known-good
- loopback connector.
-
- "IRQ determined by EPP hardware"
-
- If the Port Type is determined to be Intel EPP,
- then Parallel does not use the IRQ test, but
- rather reports the IRQ which is standard for an
- Intel EPP port at that IO Address. This only
- applies to actual Intel SL type EPP ports.
-
- "IRQ noise is present"
-
- Parallel has detected extraneous interrupts
- occuring on IRQ level 5 or 7 during the IRQ test.
-
- This condition is reported when the total number
- of interrupts occurring on both IRQ5 and IRQ7
- exceeds the number of interrupts Parallel expects.
-
- This can mean several things:
-
- 1. PIC errors. The PC's interrupt controller (PIC)
- is generating errors as described below.
-
- 2. An active device other than the parallel port
- under test is generating interrupts on IRQ 5 or 7.
- This is typically a sound card or another parallel
- port with a enabled, floating, IRQ line.
-
- 3. The port's IRQ line is electrically noisy. This
- has been seen with boards which have dual parallel
- ports where transitions in one port's IRQ line
- causes noise on the other port's IRQ line.
-
- This result may be ignored if you are not having
- any problems, but be informed that this condition
- is quite likely to confuse parallel port software
- which tries to autodetect the port's IRQ level.
-
-
- Parallel Port Information System Page 27
- ---------------------------------------------------------------------------
-
- Noisy IRQ lines can also slow down or break driver
- software which is not intelligent enough to defend
- itself against this relatively common situation.
-
- TECHNICAL NOTE: PIC errors are usually found with parallel port
- chips whose "open" condition on the ACK line may
- allow the IRQ signal to float randomly. This
- effect creates PC interrupt controller errors
- which are redirected by the PIC to IRQ7 where they
- can be mistaken for "real" interrupts.
-
- An PIC error condition is defined to occur when
- the PIC attempts to service the requesting device
- but the device's interrupt line has gone inactive.
- These are also known as "lost interrupts", which
- are not really lost but rather redirected to IRQ7.
-
- A noisy IRQ line can create the appearance of lost
- interrupts and this confuse driver software.
-
- The effect of lost interrupts being redirected to
- IRQ 7 explains why some parallel port driver
- software works well on IRQ7 but not IRQ5, or vice
- versa. The interrupt is lost, redirected to IRQ 7,
- and thus becomes found again. Strange.
-
- Parallel port interrupt handlers have to account
- for conditions that are generally not seen by
- other device drivers. If you are having problems
- with parallel port software you may want to try
- configuring the port to the other interrupt level.
-
- "Data port has stuck bits!"
-
- The rotating bit test has detected bits in the
- data port which cannot be set or cleared properly.
-
- This can mean that an enternal connection is
- preventing the datalines from makeing the expected
- transistions. You may have inserted the Loopback
- incorrectly.
-
- Of course if there is no external device present,
- then something else must be happening! It could be
- that an active device is forcing some of the data
- lines to a fixed level. It could also mean that
- your port exists, but some of the data bits are
- not working, which is a polite way of saying that
- your port is busted.
-
- A false Port Type may be reported in this case.
-
- Make sure that the loopback, if used, is correct.
- Make sure that all devices are disconnected.
-
-
- Parallel Port Information System Page 28
- ---------------------------------------------------------------------------
-
-
- "IRQ style is INVERTED"
-
- The port's IRQ line functions in an opposite sense
- from the PC standard. A significant amount of
- software will fail to work with such ports. There
- is no remedy for this condition in general; the
- best we can advise is to use a different port if
- you have a bus system or try other CMOS settings
- on a laptop if that is possible. You might try
- contacting your vendor.
-
- Parallel may falsely report inverted IRQ if there
- is an external device connected to the port.
-
- "Possible IRQ Conflict"
-
- Two or more ports in your system are using the
- same IRQ level. If you are not using interrupt-
- driven parallel port peripherals or printing
- software then you might simply ignore the warning
- if you are not experiencing any problems. However,
- you should know that some very strange results can
- occur when two parallel ports are trying to drive
- the same IRQ line. Sometimes one or both ports can
- falsely appear to have INVERTED IRQ.
-
- The best solution is to move one of the ports to
- another IRQ level, if that is possible.
-
- "BIOS Data doesn't match hardware"
-
- The contents of the BIOS LPT Table does not match
- the expected initial state at boot time.
-
- This is probably due to a parallel port device
- driver, a SWAPLPT program, or print spooler having
- fiddled with the BIOS data, in which case it may
- be considered normal operation.
-
- Network drivers (typically the redirector clients)
- also commonly rearrange the BIOS LPT Table in
- other to provide network print redirection.
-
- This information is useful if you are having
- problems with print redirection. Also, some
- parallel port device drivers do not examine the
- hardware directly to determine which ports exist,
- but rather only look at the BIOS. If you have run
- other parallel port software which has changed the
- BIOS in a non-standard way, then these device
- drivers may fail to find any parallel ports, or
- may try to access the wrong port with peculiar
- results. This can often be solved by changing the
-
-
- Parallel Port Information System Page 29
- ---------------------------------------------------------------------------
-
- order of loading or by manually configuring the
- failing driver.
-
- "Port has latent EPP tendencies"
-
- The port is an Intel SL EPP port, but it is
- currently configured to a non-EPP mode. Use your
- vendor-supplied CMOS or separate configuration
- program if you need to enable the EPP capability.
- Some vendors do not ship the ability to enable
- EPP; an appropriate utility may be available on
- the vendor's BBS.
-
- In particular, the EPP function of Compaq SL
- laptops may be enabled with their SETEPP utility.
-
- "EPP port is Intel SL flavored"
-
- The EPP port is an Intel SL port (360SL chipset).
-
- It is possible for Parallel to report a false
- Intel EPP detection on some systems. One Toshiba
- system (3600) has an 360SL onboard which does
- respond to EPP detection but is NOT connected to
- the outside world - instead their custom ASIC is
- used to implement the parallel port. So Parallel
- will report a false EPP result on this laptop.
-
- "EPP port is vanilla flavored"
-
- The EPP port is NOT an Intel SL port, but does
- pass a generic EPP write/readback test. This test
- is only attempted if the EPP BUSY line is not
- HIGH. This avoids hanging the CPU on EPP ports
- which do not implement the access watchdog timer.
-
-
- Parallel Port Information System Page 30
- ---------------------------------------------------------------------------
-
- Automatic IRQ detection
- -----------------------
-
- Parallel uses two methods for automatic detection of a port's IRQ
- level: port float or the external loopback connector.
-
- Understanding Port Float
- ------------------------
-
- Many parallel ports will "float" in a unstable logic state when
- connected to an unpowered external device such as a printer. This
- unstable logic state may cause the port to generate a limitless
- stream of apparent interrupts to the CPU if the port's interrupt
- line is enabled. This peculiar behavior is used to advantage by
- Parallel.
-
- If you have a unpowered (powered off) printer, or other device,
- attached to a port, then Parallel may be able to detect the
- interrupt level using this floating port behavior. In this case,
- Parallel will display "IRQ determined by port float". You should
- treat the IRQ determined in this way as a "best guess". To be sure
- of the IRQ, you need to disconnect the floating device and use
- loopback.
-
- In some cases, attaching a unpowered device to a port will enable
- Parallel to detect IRQ by loopback, since the combination of port
- and device appears indistinguishable from a loopback connector to
- Parallel.
-
- FLOATNOTE: Powered on devices usually hold the interrupt line in a
- stable state and prevent IRQ autodetection. Remember
- that it is best to disconnect your parallel port
- device(s) and use the loopback connector when you need
- the absolute best results from Parallel.
-
- EXAMPLE: On my home system, an unpowered HP LaserJet II printer
- on an 8bit port "floats" and Parallel reliably reports
- IRQ5. Attached to a 4bit port on the same system, the
- LaserJet is indistinguishable from a loopback
- connector. So turning the LaserJet off converts it
- into an expensive, but handy, paperclip. Turning it on
- prevents IRQ detection.
-
- TECH NOTE: Whether or not a given device and port combination will
- float, emulate loopback, or be invisible to Parallel is
- determined by the pull-ups on each end, CMOS vs TTL
- logic behavior, and the power available at the port to
- a unpowered device. In the above example, I suspect
- that enough power is provided by the 8bit TTL port to
- drive the unpowered CMOS logic in the LaserJet into an
- unstable oscillating state, which appears to the system
- as a frenzy of level 5 IRQs.
-
- Port float is a handy effect, but use Loopback for best results.
-
-
- Parallel Port Information System Page 31
- ---------------------------------------------------------------------------
-
-
- The most reliable way to determine IRQ is to use an external
- loopback connection. Loopback is described in the next section.
-
- IRQ detection using the LoopBack Feature
- ----------------------------------------
-
- ******************
- * IMPORTANT NOTE *
- ******************
-
- First, DECIDE NOT TO SCREW UP YOUR PORT by crudely jamming wires
- into the wrong places with too much force. REMEMBER that the
- female DB-25 connector is likely to be made out of CHEAP, BREAKABLE
- PLASTIC, so decide right now not to break it. WE ARE NOT LIABLE FOR
- ANY DAMAGE YOU MAY DO FOR WHATEVER REASON.
-
- The danger is that you will push too hard when inserting the
- loopback wire and force the female connector pin out of its
- position in the DB-25 shell. That is why WE SUGGEST MAKING A
- LOOPBACK PLUG using a male DB-25 connector as described below. If
- you cannot make a loopback plug, then use a parallel port extension
- cable instead. This protects your port from physical damage and
- also makes it a lot easier to work with.
-
- The port is supposed to be electrically designed to tolerate the
- loopback perfectly well. However there is a DANGER OF DAMAGE BY
- STATIC DISCHARGE so make sure that you GROUND YOURSELF TO THE PORT
- before inserting the loopback wire. It would be terrible if you
- blew out a $25 parallel port on a $1000 Pentium motherboard simply
- because you failed to PAY ATTENTION TO THESE PRECAUTIONS.
-
- PROCEED AT YOUR OWN RISK.
-
- The other danger is that you will apply the loopback to a port
- which is not really a parallel port at all. DON'T DO THIS. If you
- are not sure of what you are doing STOP RIGHT NOW. We have no
- control over what you might damage if you try this with a port
- other than a parallel port.
-
- Whew... now on with the instructions.
-
- 1. Find the parallel port(s) you want to test. They will be
- female DB-25 connectors. MAKE SURE THAT YOU HAVE CORRECTLY
- IDENTIFIED THE PARALLEL PORT. Disconnect any devices
- (printers, network adapters, external disks, etc) which might
- be attached to other parallel ports on your system.
-
- 2. Make sure that the connector IS NOT SOME OTHER TYPE OF
- CONNECTOR like an external SCSI connector or a COM port.
-
- SCSI ports can be either female DB-25s or a larger connector,
- like a 37, 40, or 50-pin connector. COM ports are usually
-
-
- Parallel Port Information System Page 32
- ---------------------------------------------------------------------------
-
- male DB-25 or small male DB-9 connectors, but this is not
- guaranteed.
-
- Look in your manual if there is any doubt. DON'T PROCEED
- unless you are sure you have identified the parallel port(s)
- correctly.
-
- 3. Connect the Loopback Plug and go to Step 7.
-
- If you do not have a Loopback Plug, use a straight thru M-F
- parallel port extension cable to prevent damage to your port.
- Connect the male end of the extension cable to your port and
- place the loopback wire into the female end of the cable.
-
- |---
- expensive | | +-+ cheap +-+
- PC | | | |---------------| | <- loopback here
- parallel port | | +-+ cable +-+
- |---
-
- 4. Identify Pin 10 and Pin 9 on the female end of the extension
- cable. Refer to the illustration below. Notice that a DB-25
- connector is wider on one side. The pins you want are the
- 4th and 5th from the left on the wider edge.
-
- USE A FLASHLIGHT TO FIND THE MARKINGS IF YOU HAVE ANY DOUBT.
-
- Front View -------- Pin 10 - 4th from left on wider edge
- Female DB-25 | ---- Pin 9 - 5th from left on wider edge
- Connector | |
- v v
- ____________________________________________________________
- / \
- \ 13 12 11 10 9 8 7 6 5 4 3 2 1 /
- \ /
- \ 25 24 23 22 21 20 19 18 17 16 15 14 /
- \______________________________________________________/
-
- Pin 10 is the interrupt line (the ACK line)
- Pin 9 is the high order data line (the 80h bit)
-
- 4. Create a loopback wire. A standard paperclip works fine. Just
- straighten it out and bend it into a "U" shape with the ends
- 1/8 inch apart. Make sure that the paperclip is SMOOTH and
- has NO ROUGH EDGES that might damage the plastic connector.
-
- 5. GROUND YOURSELF to the PC and to the parallel port by
- touching your hand and the loopback wire first to the PC's
- metal chassis near the parallel port connector and then to
- one of the connector nuts or the connector metal housing
- itself. Do this to DISCHARGE ANY STATIC ELECTRICITY you may
- have about you (created for example by scooting across the
- rug in a silk negligee on the way to your PC or by stroking
- your cat with woolen gloves while purusing this document).
-
-
- Parallel Port Information System Page 33
- ---------------------------------------------------------------------------
-
-
- Parallel ports are usually resistant to static discharge, but
- not all ports are created equally, so don't ask for trouble.
-
- 6. Carefully insert the paperclip into the extension cable's
- female DB-25 connector so that Pin 9 is connected to Pin 10.
- DON'T FORCE IT. It will insert at most about 1/4 inch (about
- .5 cm) and there should be absolutely no physical resistance.
-
- 7. Now run Parallel. It will automatically use the loopback to
- determine which IRQ level the port is actually using. You may
- loopback more than one, or all, ports at the same time.
-
- Parallel will report that is has detected a proper loopback.
-
- 8. Remove the loopback when you are done.
-
- 9. Congratulate yourself on using reasonable handling
- precautions when working with expensive equipment.
-
-
- TechNote: Making Your Own Loopback Connector
- --------------------------------------------
-
- We strongly advise that you make a loopback connector, inside of
- using the expedient paperclip approach.
-
- Simply obtain a male DB-25 connector and solder a permanent
- connection bewteen Pin 9 to Pin 10 on the back of the connector.
-
- Male DB-25 connectors are inexpensive and available in electronics
- parts stores. Cheap DB-25 jumper boxes cost only a few dollars.
-
- This will prevent any physical damage to your port, which is the
- major source of risk with this procedure, and the reason for our
- incessant nagging about precautions. This sort of loopback
- connector will be no more dangerous to your system than a printer,
- and is a handy accessory if you frequently use Parallel.
-
- Connect Pin 10 to Pin 9
-
- Back View ----- Pin 10 - 4th from left on wider edge
- Male DB-25 | | Pin 9 - 5th from left on wider edge
- Connector | |
- v v
- ____________________________________________________________
- / \
- \ 13 12 11 10 9 8 7 6 5 4 3 2 1 /
- \ /
- \ 25 24 23 22 21 20 19 18 17 16 15 14 /
- \______________________________________________________/
-
- Pin 10 is the interrupt line (the ACK line)
- Pin 9 is the high order data line (the 80h bit)
-
-
- Parallel Port Information System Page 34
- ---------------------------------------------------------------------------
-
- Miscellaneous Topics
- --------------------
-
- Technote: Pseudo-Bidirectional Ports, A Special Case
- ----------------------------------------------------
-
- A 4bit port is pseudo-bidirectional (also called pseudo-8bit,
- sometimes semi-8bit) when it is capable of performing 8BIT input
- when connected to a device which has strong drivers. So this
- pseudo-bidirectionality comes about as the relationship between the
- port and the device it is connected to.
-
- This type of port will appear to be a 4BIT port with most parallel
- port external peripherals, since low power CMOS drivers are by far
- the most common in these external devices.
-
- A few peripherals have stronger TTL drivers which can achieve 8BIT
- operation by overdriving the port. There are even sub-classes of
- ports which can achieve the effect depending on what data is used.
-
- Some vendors describe their ports as bidirectional when actually
- they are only pseudo-bidirectional and will function as 4BIT ports
- with most peripherals. True 8BIT ports are preferable because they
- have a significant speed advantage with most external peripherals.
- Indeed, some parallel port peripherals require true 8BIT behavior.
-
-
- Identifying pseudo-bidirectional ports
- --------------------------------------
-
- Step 1 => Read the cautions and disclaimers applying to loopback
-
- Step 2 => Read them again
-
- Step 3 => Select the port. The test only applies to 4BIT ports.
-
- Step 4 => Attach a parallel port extension cable to the port
-
- Step 5 => At the female DB-25, loopback Pin 8 to Pin 21 (GND).
-
- Step 6 => Run Parallel
-
- Step 7 => If Parallel reports "Data port has stuck bits" then the
- port is likely to have semi-bidirectional capability.
-
-
- Parallel Port Information System Page 35
- ---------------------------------------------------------------------------
-
- Parallel Port Standards
- -----------------------
-
- 4bit and 8bit parallel ports
- ----------------------------
-
- There is no true standard for these types of ports other than
- the actual behavior of existing systems.
-
- The original IBM PC Technical Reference manual gave a schematic
- for the parallel port which was ambiguous about the ability to
- input from the printer port.
-
- Various vendors interpreted the ambiguity differently ... and
- this appears to have been the genesis of a persistantly loose
- and confused industry attitude toward parallel port standards.
-
-
- EPP Specification
- -----------------
-
- There are two substantially incompatible standards for EPP
- parallel ports: the original EPP Standards Committee version 1.7
- standard, and the IEEE 1284 Committee standard.
-
- We call these two types of EPP ports "EPP 1.7" and "EPP 1284".
-
- The two standards are sufficiently similar that new peripherals
- may be designed in such a way as to support both standards, but
- existing EPP 1.7 peripherals will generally not operate with EPP
- 1284 ports.
-
- The reference implementation of EPP 1.7 is the Intel 360SL chip.
-
- There are several implementations of EPP 1284 including the SMC
- 66x, the National PC87xxx family, and perhaps others. Chipset
- vendors are rapidly adding advanced parallel port functionality
- to their product lines. We will continue to review these chips
- as they appear from other manufacturers.
-
- ECP Specification
- -----------------
-
- The ECP port standard was developed by Microsoft and Hewlett-
- Packard. The standard specifies a PC parallel port with certain
- I/O registers and features and an external signalling behavior.
-
- The external signalling specification has been incorporated into
- the IEEE 1284 specification as the ECP mode of 1284.
-
- Reference implementations of ECP include the SMC 66x, the
- National PC87xxx, and others. These chips vary in the processes
- required to configure, and specific PC implementations will vary
- in their setup and/or BIOS support.
-
-
- Parallel Port Information System Page 36
- ---------------------------------------------------------------------------
-
-
- IEEE 1284 Specification
- -----------------------
-
- The IEEE 1284 specification defines the electrical signalling
- behavior external to the PC for a multimodal parallel port which
- may support 4bit, 8bit, EPP, and ECP modes of operation. Not all
- modes are required by the 1284 specification and the standard
- allows makes some provision for additional modes.
-
- The IEEE 1284 standard is targeted at specifying the behavior
- between a PC and an attached device, most specifically attached
- printers, although the specification is of interest to vendors
- of parallel port peripherals (disks, LAN adapters, etc, etc).
-
- The IEEE 1284 standard is currently maintained by Larry Stein of
- Farpoint Communications (see Vendor Contact section).
-
- The IEEE standard has additional "substandards", including IEEE
- 1284.3 (daisychain and multiplex standard) and the committee is
- beginning work on operating system standards and certification
- processes. The IEEE 1284 style parallel port is required for PCs
- to comply with the PC95 platform specification. We know of no
- parallel port implementations with native plug-and-play support.
-
- Various non-PC/DOS/Windows hardware and software vendors (Sun,
- Apple, Next) have shown interest in the committee's efforts. It
- is very likely that future versions of Windows will support the
- 1284 specification, at least in the area of high-speed printing.
-
- The 1284 specification will also likely be approved as a
- component of the Desktop Management Task Force (DTMF) standard
- for PC resource management.
-
- The downside of the IEEE 1284 specification is that it does not
- specify the PC's internal interface to a 1284 compliant parallel
- port, either at the ISA register level or a software API level.
- Each chipset vendor is implementing subtly different behaviors
- in their chipsets, especially as regards configuration and setup
- - a process which is recreating the same system and software
- management mess that exists on earlier generations of parallel
- port technology. In order words, the IEEE 1284 specification
- does not answer the basuc question "What is a parallel port and
- how do I perform I/O to it?".
-
- Perhaps the Committee's efforts will successfully expand to
- provide a unified solution, and perhaps such efforts will again
- be too little, too late in the technology curve to achieve a
- unified practical standard.
-
- To date, the IEEE 1284 standard does not represent a unified
- solution to the challenges and potential of future parallel port
- technology. It represents a tolerable, if uninspired, next step
- in the evolution of particular classes of the technology.
-
-
- Parallel Port Information System Page 37
- ---------------------------------------------------------------------------
-
-
-
- Parallel Port Standards Diagram
- -------------------------------
-
- The following diagram attempts to depict the interrelatedness of
- various standards affecting the PC parallel port. It is useful
- to keep in mind the distinctions between systems, interfaces,
- port designs, and specific chips when considering parallel port
- issues. Since the parallel port has been a "poor relation" in
- the evolution of these standards, there are gaping holes in the
- overall standarization process.
-
- For example, there is no standard for hardware independent I/O
- to any parallel port and device. Existing proposed standards
- are inadequate to the purpose. Such a standard must provide a
- level of adaptive flexibility in expanding dynamically to
- incorporate new instances of ports, devices, and I/O methods.
-
- Actually, the Plug-and-Play standards concept is an interesting
- paradigm for such a parallel port software standard, which would
- treat ports, devices, and I/O methods as pluggable entities in a
- comprehensive and real-time extensible software architecture.
-
- -------------------------------------------------------------------
- |
- Platform | PC95 Platform DTMF Individual
- Level | Standard Standard Operating System
- Standards | Software Standards
- | ^
- ------------------------------------------------------------|------
- | |
- Interface | IEEE 1284 Interface possible future IEEE |
- Standards | Standard software standards --- ?
- |
- -------------------------------------------------------------------
- |
- PC Port | EPP 1.7 Port MS/HP ECP Port
- Standards | Standard Standard
- |
- -------------------------------------------------------------------
- | C&T
- Specific | Intel SMC National Cirrus Logic
- Chips | 360SL 66x PC87xxx StarTech
- | others
- |
- -------------------------------------------------------------------
- |
- Example | SL laptops Intel IBM unknown
- Specific | with 360SL Pentium ThinkPad or
- Systems | or equiv. Mthrbrd 755 forthcoming
- |
- -------------------------------------------------------------------
-
-
- Parallel Port Information System Page 38
- ---------------------------------------------------------------------------
-
- Parallel Port Buyer's Guide
- ---------------------------
-
- This Guide is intended to serve as a starting point for user's in
- search of quality parallel ports and peripheral devices.
-
- Parallel Technologies makes no warranties regarding these products
- and indeed we remind you to independently verify that the product
- will perform as expected in your environment.
-
- Parallel's evaluation and recommendation policy is:
-
- 1. We recommend only those products that we ourselves have
- tested extensively.
-
- 2. We make only positive recommendations. Inferior products will
- generally NOT be mentioned unless we consider them patently
- offensive to the user.
-
- 3. Vendors are invited to arrange evaluations of their products
- so that they may be included in the Buyer's Guide. We will
- evaluate the product and propose a short description of it's
- capabilities, features, and quality. The vendor has the
- option of requesting that the product not be listed.
-
- 4. We are planning to expand the coverage in the Buyer's Guide
- to include parallel port peripheral devices: LAN adapters,
- disks, SCSI adapters, CDROMs, and so forth. Again, interested
- vendors are welcome to arrange and actively contribute to a
- review of their product. The "no-pan" rule will apply.
-
- Direct Sales suppliers of products are listed in those cases where
- such suppliers are known and have proven reliable in the past.
-
- See the Vendor Contact section for specific vendor information,
- including telelphone numbers and email addresses, if applicable.
-
-
- 4bit parallel ports
- -------------------
-
- This type of port is not recommended. Although most external
- parallel devices will support this type of port quite well, it
- is considerably slower at input operations than all other port
- types and has no cost advantages. At a minimum, get an 8bit
- port or better yet, one of the advanced port types (EPP, ECP, or
- a multimodal port which support both EPP and ECP).
-
- 8bit parallel ports
- -------------------
-
- 8bit parallel ports are adequate for CURRENT printing purposes
- and may be used with all parallel port devices. However, you
-
-
- Parallel Port Information System Page 39
- ---------------------------------------------------------------------------
-
- should consider buying an advanced parallel port (particularly
- an EPP/ECP capable multimodal port) when buying new systems.
-
- Mfg & Model Features Suppliers
- -------------- ----------------------------- ---------------
-
- STB DSP 550 basic 2S+P ISA add-in card Essential Data
- requires jumper for 8bit mode JAZ COmputer
- has 16550 serial ports
-
- -------------- ----------------------------- ---------------
- Everex MagicIO very clean signals
- hard to find
-
- -------------- ----------------------------- ---------------
- other 8bit generic 2S+P I/O cards
- Parallel reliably detects them
- highly variable quality
-
- -------------- ----------------------------- ---------------
- QuickPath multifunction ISA add-in card Essential Data
- PortFolio IDE, 4 floppy, game port
- 4 serial ports with 16650's
- 2 parallel ports
-
-
- EPP Parallel Ports
- ------------------
-
- EPP-capable parallel ports are generally found only on laptops,
- as a result of their introduction on the Intel 360SL I/O chip
- which was part of the SL chipset designed for laptops. We have
- listed one supplier (FarPoint) for a ISA add-in card suitable
- for desktops.
-
- Be sure that you identify the VERSION of EPP support the port
- provides, EPP 1.7 or IEEE 1284 EPP.
-
- EPP 1.7 is the older Intel-style EPP which is
- compatible with many existing parallel port devices
- such a Xircom LAN adapters, Trantor SCSI adapters,
- SyDOS cartridge disks, and so forth.
-
- IEEE 1284 EPP is a new specification for EPP which is
- not completely backward-compatible with the EPP 1.7.
- This means that most existing parallel devices do not
- work with IEEE 1284 EPP.
-
- Tech Note: It is possible to design parallel port devices so that
- they are compatible with BOTH the EPP 1.7 and 1284 EPP
- specs, however existing devices typically don't do this
- yet. Existing devices generally support only EPP 1.7.
-
-
- Parallel Port Information System Page 40
- ---------------------------------------------------------------------------
-
- If you are buying a parallel port device (LAN, Disk,
- CDROM, etc, etc) for general use, consider holding out
- for a version that support BOTH EPP 1.7 and IEEE 1284
- EPP or ECP modes of operation. This gives you support
- for the large installed base of SL style laptops and
- compatibility with future system where IEEE 1284 style
- ports will predominate.
-
- Mfg & Model Features Supplier
- -------------- ----------------------------- ---------------
- Intel SL-based any laptop fully implementing many and varied
- laptops Intel 360SL compatibility
- or compatibles more than 50 models available
- provides EPP 1.7 capability
-
- -------------- ----------------------------- ---------------
- Farpoint Fport ISA add-in card with EPP 1.7 Farpoint
- downloadable personalities
- has extra useful IO addresses
- has extra useful IRQ levels
- good documentation
- value-added software for
- port configuration and drivers
- for fast DOS / NOVELL printing
- excellent tech support
-
- When buying an EPP-capable laptop for use with EPP external
- peripherals, it is important to BE VERY CLEAR about what you are
- getting. Even different models from the same manufacturer will
- have different implementations of EPP. CHECK COMPATIBILITY with
- the specific peripherals you intend to use.
-
- Example 1: Various SL-based Compaqs (SL25s, Conturas) have long
- has excellent implementations of EPP 1.7. However the more
- recent Compaq Aero appears to have a unique implementation which
- is not fully SL compatible.
-
- Example 2: The IBM Thinkpad 750 has an SL-compatible EPP 1.7
- port, but the 755 model has a non-SL-compatible EPP port.
- Devices which work on one 700 model do not work on another.
-
- NOTE: This is not an indictment of these laptops by any means,
- as they as fine systems overall. It IS A REMINDER that you must
- independently verify the current state of compatibility between
- any particular EPP-capable laptop and parallel devices you plan
- to use with them. Laptop vendors generally will not know the
- answers to your questions about parallel ports and the best bet
- is the peripheral vendor.
-
- EPP 1.7 type parallel ports MAY OR MAY NOT be supported by any
- specific new IEEE 1284 type peripheral. We predict that most
- developers of new devices will want to support EPP 1.7 in order
- to be compatible with the install base of SLs, however they may
-
-
- Parallel Port Information System Page 41
- ---------------------------------------------------------------------------
-
- opt to just support IEEE 1284 style EPP which leaves the SLs up
- the creek. It is possible to support both.
-
- So there is a certain risk factor in buying a laptop with only
- EPP 1.7 support today ... as an increasing number of systems are
- appearing with multimodal 1284 style ports. On the other hand,
- buying a laptop without EPP 1.7 leaves you incompatible with a
- large variety of existing external peripherals - you will have a
- bit of a wait as peripheral vendors scurry to support IEEE 1284.
-
- In the best of worlds, you will buy a system which supports all
- the IEEE 1284 modes, EPP 1.7 to boot, and comes with a handy
- utility which allows you to configure your port easily.
-
-
- ECP Parallel Ports
- ------------------
-
- There are some very nice chipsets coming out for multimodal
- parallel ports which support the multiple parallel port modes.
-
- These chipsets have been appearing in systems since early this
- year and have just now reached the stage where they are safe
- consumer choices given a little caution.
-
- In some cases, early "steps" of particular chips had significant
- flaws and the buyer should verify that he is getting the latest
- step - not something that's been in a warehouse since Easter.
-
- Vendors may or may not provide user level support for selecting
- the parallel port mode. Check that any PC you are considering
- has appropriate CMOS port configuration or at least a separate
- utility for the purpose. Be aware that vendors may have BIOS
- upgrades which retroactively enable such support.
-
- If you need immediate support for existing parallel port devices
- operating in EPP mode you should INDEPENDENTLY VERIFY that the
- device works with the particular system you are considering. Be
- aware that existing EPP 1.7 type devices may or may not work
- with any particular new multimodal parallel port. It is still
- early days yet for ECP support in parallel port devices and this
- caution also applies to any early versions of such devices you
- might consider - check that they work with your specific system.
-
-
-
- Mfgr & Model Features Supplier
- -------------- ----------------------------- ---------------
- Intel Premiere motherboard with SMC 665 chip used in many
- Pentium PCI 66xQPF chip has various bugs Pentium systems
- Motherboard be sure you get the 665GT chip from various
- requires Plato version 10 BIOS "manufacturers"
- to enable EPP/ECP in Setup
-
-
- Parallel Port Information System Page 42
- ---------------------------------------------------------------------------
-
- -------------- ----------------------------- ---------------
- Other systems be sure you get the 665GT chip various
- with SMC 66x check for software support
-
- -------------- ----------------------------- ---------------
- SIIG IDE multifunction ISA add-in card superstores, etc
- Professional IDE, floppy, 2serial, parallel
- uses the SMC 66x chip
- again, avoid the QPF version
- no port configuration software
- no value-added software
- decent jumper documentation
-
- -------------- ----------------------------- ---------------
- Farpoint ISA add-in card with SMC 66x Farpoint
- Fport Plus serial and parallel port only
- good configuration utility
- fast DOS / Windows driver
- 1 16650 serial port
- excellent tech support
-
- -------------- ----------------------------- ---------------
- Farpoint ISA add-in card with SMC 66x Farpoint
- Fport IDE IDE, 2 serial, parallel
- good configuration utility
- fast DOS / Windows driver
- 2 16650 serial w/ extra IRQs
- excellent tech support
-
- -------------- ----------------------------- ---------------
- Kouwell typical clone SMC 66x ISA card Essential Data
- IDE, 2 16550 COM, parallel,
- no value added software
- very low cost
- check that you get the GT step
-
- Advanced Parallel Port Chipsets
- -------------------------------
-
- Mfg & Model Features Supplier
- -------------- ----------------------------- ---------------
- SMC 66xQPF multifunction I/O chip SMC
- multiple parallel port modes
- IEEE 1284 EPP and ECP
- no EPP 1.7
- has bad serial port FIFO bug
- EPP mode has minor bugs
- good chip, but use the GT step
-
- -------------- ----------------------------- ---------------
- SMC 66xGT corrected version of 66xQPF SMC
- IEEE 1284 EPP and ECP
- adds EPP 1.7
- fixes various bugs, com FIFO
-
-
- Parallel Port Information System Page 43
- ---------------------------------------------------------------------------
-
-
-
- -------------- ----------------------------- ---------------
- National PC87xxx SuperI/O chip family National
- Semiconductor 322 is EPP 1.7 only
- 332, 334, 303, 323, and 306
- have EPP 1.7, EPP 1284 & ECP
- various features on chips:
- IDE, 16650 serial, floppy,
- keyboard, clock, serial IR
- 5 volt and 3.3 volt versions
-
- -------------- ----------------------------- ---------------
- Chips & information not available C&T
- Technologies at this time, watch this space
-
-
- Parallel Port Information System Page 44
- ---------------------------------------------------------------------------
-
- Vendor Contact Information
- --------------------------
-
- Parallel Technologies Jay Lowe, VP 206-869-1136 voice
- parallel port wizards CIS 76640,203 206-869-1133 fax
- contract development Don Schuman, Pres
- product licensing CIS 72242,3631
- DirectConnect(TM)
- technology licensing
-
- FarPoint Communications Larry Stein 805-726-4420
- direct sales vendor CIS 71514,1057
- specialize in parallel IEEE 1284 chairman
- very experienced
-
- Essential Data Bruce McKeag 800-795-4576 voice
- direct board sales CIS 70572,2670 408-955-0440 voice
- active on Compuserve 408-955-0821 fax
-
- JAZ Computer Products J. Zarifis 914-632-9531 voice
- direct board sales CIS 71042,1251
- GEnie J.ZARIFIS
-
- Standard Microsystems Robert Gross
- chipset vendor
-
- National Semiconductor Kishor Padmanabhan 408-721-4563
- chipset vendor
-
- Chips & Technologies forthcoming
- chipset vendor
-
- IEEE 1284 Committee Larry Stein 805-725-4420
- CIS 71514,1057
- - also -
- EET:STDFRM CIS forum
-
-
-
-
- Reputable vendors of parallel port technology are invited to
- forward us a short listing of their interests
- and contact information for inclusion here.
-
-
- Parallel Port Information System Page 45
- ---------------------------------------------------------------------------
-
- Technical Support
- -----------------
-
- Parallel is Freeware, and comes with Freeware-style support. It has
- been extensively tested with a range of systems from original PCs
- to Pentiums and works with all parallel port devices we've seen.
-
- We are willing to offer friendly assistance on an as-available
- basis, but only via Compuserve mail (CIS 76640,203), via Internet
- Email to jaylowe@halcyon.com. or in the Compuserve IBMHW forum.
-
- Alas, we do not offer free telephone assistance to the public.
-
- If you are in dire need of technical support in solving port
- related problems, you may open a support account by contacting:
-
- Mailing Address Shipping Address
- --------------------------- ---------------------------
- Parallel Technologies, Inc. Parallel Technologies, Inc.
- PO Box 7 10603 170th CT NE
- Redmond, Wa 98073-0007 Redmond, Wa 98052
- (206) 869-1136
- (206) 869-1133 (fax) ( for UPS, FEDEX, etc )
- Compuserve: 76640,203
- InterNet: 76640.203@COMPUSERVE.COM
- -or- : jaylowe@halcyon.com
-
- Custom versions of the Parallel Port Information Utility, and
- source code, are available.
-
- Vendors of parallel port hardware are invited and requested to
- contact us so that we may ensure that Parallel is compatible with
- their products.
-
- Permission is given to distribute and use Parallel without charge,
- provided you adhere to the terms and conditions of the license
- agreement given below. Specifically, you may not charge anyone for
- for sharing or using Parallel, and you may not modify it or change
- it. Nor may you use it as part of a commercial product or service
- without our written permission.
-
- Vendors may freely distribute Parallel on an individual basis,
- without charge, by electronic BBS or other means. However, you may
- not include it in or with your product without our written
- permission.
-
- We welcome your comments and suggestions by Email, phone, or fax.
-
- If you have particular features you would like to see supported by
- Parallel, we'd be more than glad to hear from you.
-
-
- Parallel Port Information System Page 46
- ---------------------------------------------------------------------------
-
- About Parallel Technologies, Inc.
- ---------------------------------
-
- We at Parallel Technologies' have been creating innovative parallel
- port devices and software since 1989. Here are a few highlights:
-
-
- Firsts, Bests, and Mosts
- ------------------------
-
- o 1st ... parallel port network adapter
- o 1st ... enhanced, bus-speed, parallel port
- o 1st ... parallel port external SCSI disk
- o 1st ... passthrough printing capability
- o 1st ... automatic self-configuring drivers
- o 1st ... universal support for all types of parallel ports
- o 1st ... network adapters with multiple media support
- o 1st ... Windows 3.1 multimedia driver for parallel adapter
- o 1st ... Multiple Parallel Device API for shared devices
- o 1st ... intelligent parasitic power for self-powered devices
- o 1st ... demonstration of daisychained parallel peripherals
- o 1st ... demonstration of multiplexed parallel peripherals
- o 1st ... Parallel Port Expansion System (now IEEE Multiport)
- o 1st ... Parallel Port Developer's Kits
- o 1st ... general purpose parallel port networking (DirectNet)
- o 1st ... Win 95 parallel port networking (DirectNet VCOMM)
-
- o PC MAG Editor's Choice for Ethernet parallel port NIC
- o most total network adapters -- 7 and counting...
- o most total parallel port peripherals -- 25 and counting...
-
-
- Partial List of Parallel Technologies' Developments
- ---------------------------------------------------
-
- o parallel port Arcnet adapter
- o parallel port Ethernet Adapter (two versions)
- o parallel port Token Ring Adapter (two versions)
- o parallel port portable SCSI disk drive
- o parallel port portable IDE disk drive
- o parallel port MIDI interface for Windows
- o parallel port Zero-Slot mouse adapter
- o parallel port IR Wireless Adapter
- o parallel port DSP signal processing interface
- o parallel port Multiport daisychaining system
- o parallel port Multiport 4-way parallel device multiplexor
-
- o DirectNet ODI driver for parallel port networking
- o DirectNet VCOMM driver for parallel port networking
-
- o DirectNet 4BIT cables for parallel port networking
- o DirectNet ECP cables for parallel port networking
- o DirectNet Universal cables for parallel port networking
-
-
- Parallel Port Information System Page 47
- ---------------------------------------------------------------------------
-
- o DirectNet 4BIT/ECP and UCM cable interface specification
- licensed to Microsoft for joint Microsoft/PTI publication
-
- o Parallel Port Developer's Kit (Level 1)
- o Parallel Port Developer's Kit (Level 2)
- o Super IEEE 1284 Printing System Developer's Kit
- o DirectNet Parallel Port Networking Manufacturing License Kit
- o DirectNet Parallel Port Networking Software License Kit
-
-
- Many of these products, or their hardware and software components,
- are available for OEM licensing.
-
- We have in-depth experience with the wonderful and sometimes
- bizarre world of the PC parallel port and have served on both the
- EPP and IEEE 1284 standards committees. Having created more than
- TWO DOZEN parallel port devices with their associated drivers and
- software utilities, we are the most experienced source for off-the-
- shelf technology, developer tools, and contract services.
-
- Here are a few of our current and forthcoming products that you may
- find interesting.
-
-
- Parallel Port Developer's Kits
- ------------------------------
-
- Parallel Technologies offers parallel port Developer's Kits which
- contain those hardware and software components necessary to build
- very high-speed, consumer-quality external devices.
-
- The Developer Kit technology has been used in over 25 parallel port
- devices including network adapters, parallel port SCSI and IDE
- disks, parallel port wireless IR adapters, parallel port MIDI and
- mouse interfaces, parallel to serial interfaces, and so forth.
-
- The software includes support for all types of ports, IO code that
- is extremely resistant to port idiosyncrasies, and full auto-
- detection of all port hardware features. The code is very well
- documented. A selection of sample drivers for parallel port devices
- is also available.
-
-
- Level One Developer's Kit
- -------------------------
-
- Hardware schematics, timing diagrams, access methods
- and all other hardware information required to
- implement basic peripheral devices that are compatible
- with 4BIT, 8BIT, semi-8BIT,and EPP parallel ports
-
- The software section includes sample source code for
- register and block data access to the sample device.
-
-
- Parallel Port Information System Page 48
- ---------------------------------------------------------------------------
-
-
- Level Two Developer's Kit
- -------------------------
-
- Includes the Level One Kit PLUS
-
- additional very high speed IO techniques,
- passthrough port design techniques
- daisychain and multiplexor Multiporting design
- additional ECP hardware design techniques
- additional source code for ECP I/O techniques
-
- full source code for Parallel autodetect utility
-
- Also includes full EPP and IEEE 1284 specifications.
-
- Super IEEE 1284 Developer's Kit
- -------------------------------
-
- Prototyping board, printer side interface FPGA
- equations, assembler source for 1284 negotiation,
- Windows 3.1 driver source.
-
- Allows the rapid development of IEEE 1284 printers.
-
- Also Super 1284 goes BEYOND the IEEE 1284 spec to allow
- very high-speed bi-directional I/O on 4BIT, semi-8BIT,
- and 8BIT ports. This means that Super 1284 printers
- can operate bi-directionally at very high speeds
- (upwards of 300Kbyte/sec) even on the installed base of
- "old-fashioned" standard parallel ports.
-
- Super 1284 maintains complete compatibility with IEEE
- 1284 ports and printers. It is a compatible enhancement
- that allows printer vendors to support high-speed
- operation without requiring EPP and ECP ports.
-
- DirectNet -- The Parallel Port Networking System
- ------------------------------------------------
-
- The DirectNet parallel port networking system has been
- incorporated into Windows 95 and may be licensed for
- inclusion in other operating environments.
-
- The DirectNet system is a family of completely external
- connection devices and network driver software that
- allows PC-to-PC plug-and-play cable connections to be
- used as an alternative to more expensive LAN hardware.
-
- The DirectNet hardware technology includes 3 point-to-
- point cables, and multiport hub, and a distributed
- multdrop system which uses RJ-11 standard phone wiring.
-
-
- Parallel Port Information System Page 49
- ---------------------------------------------------------------------------
-
- DirectNet supports speeds of 40 - 500+ KBytes/sec
- depending on the parallel ports involved and various
- other factors. The system is completely self-adaptive.
-
- Because DirectNet provides a suite of standard network
- drivers, it may be used with many existing networking
- and connectivity systems such as Windows 95, Windows
- for Workgroups, Netware Lite and Personal Netware, etc.
- DirectNet connections have been tested with more than a
- dozen commonly available networking and connectivity
- software packages.
-
- DirectNet is now in a BETA RELEASE status and Parallel
- Technologies is providing manufacturing and software
- licenses vendors who wish to include DirectNet products
- or capability in their product lines.
-
-
- Parallel -- the Parallel Port Information Utility
- -------------------------------------------------
-
- A handy utility which examines your system's parallel
- ports and reports the Port Type, IO address, IRQ level,
- BIOS name, and an assortment of informative notes and
- warnings in a compact and easy to read display. The
- output may be redirected to a file for tech support
- purposes. Parallel uses very sophisticated techniques
- for port and IRQ detection and is aware of a broad
- range of quirky port features.
-
- Parallel is the definitive parallel Tech Support tool.
-
- Parallel is Freeware, subject to a restricted license
- agreement. It may be used free of charge for any
- personal, non-commercial purpose. Parallel may not be
- sold for profit, nor may it be distributed with any
- other product sold for profit. Vendors should contact
- us regarding commercial licenses.
-
-
- OEM Products
- ------------
-
- Most of our products are available for OEM licensing,
- including network adapters, EPP-capable hard disks,
- parallel-SCSI interface, parallel MIDI adapter, and the
- MultiPort parallel port expansion system.
-
- Also available are numerous off-the-shelf hardware and
- software components including: device schematics, FPGA
- equations, DOS and Windows driver source code, etc.
-
-
- Parallel Port Information System Page 50
- ---------------------------------------------------------------------------
-
- Development Services
- --------------------
-
- We specialize in contract development of parallel port
- peripherals and associated software including DOS and
- Windows device drivers. Our broad and deep experience
- with parallel port devices and our commitment to
- specialization allows us to design, implement, test,
- and support them very efficiently.
-
- You might be interested in our 45/90 development offer.
-
- We propose to convert almost any ISA peripheral into a
- parallel port device in only 45 days to prototype, 90
- days to production.
-
- We also offer more limited development support, such as
- developing additional device drivers or enhancements
- for existing peripherals.
-
- We are quite experienced with EPP and ECP ports and are
- ready to upgrade your existing parallel port devices
- for peak performance.
-
-
- Consulting and Training
- -----------------------
-
- In support of in-house development, you will find our
- consulting and training services invaluable in avoiding
- the pitfalls of parallel port development - and achieve
- the highest possible product performance and quality.
-
- We conduct in-house trainings and design consultations
- in hardware, software, and product design / management.
-
- You may find these trainings useful in bringing your
- development and management team up to speed on parallel
- port issues.
-
-
- Parallel Port Information System Page 51
- ---------------------------------------------------------------------------
-
- Software License Agreement
- --------------------------
-
- IMPORTANT
-
- Read this agreement before installing or using the Software. Installing
- and/or using the Software on your computer indicates your acceptance of
- these terms. If you do not agree to these terms and conditions, delete
- the Software and all it's associated files from your computer. This
- Software License Agreement gives you ONLY RESTRICTED RIGHTS to use the
- Software (and all it's associated files and documentation) as follows:
-
- YOU MAY
-
- 1. Use the Software without charge on as many systems as you wish,
-
- 2. Share the Software with others for their personal use, but only
- if you share it intact, without any changes or modifications of
- any kind, and complete with all it's documentation and associated
- files. You must pass it on exactly in the same form as we release
- it, or not pass it on at all.
-
- 3. Make backup copies of the Software, so long as you place our
- copyright notice on the backup copies,
-
- 4. Request and receive limited technical support as provided in the
- Freeware Product Support Policy below.
-
- 5. Vendors may distribute the Software free of charge by electronic
- or other means for the purpose of technical support, but may not
- include the Software in products without our written permission.
-
- YOU MAY NOT
-
- 1. Use the Software in any way except as provided in this agreement,
-
- 2. Modify, alter, copy, transfer, or reproduce the Software in any
- way, except as expressly allowed in this agreement,
-
- 3. Translate, de-assemble, de-compile, reverse program, or reverse
- engineer the Software or any of its components,
-
- 4. Charge any kind of fee for distributing the Software without our
- written permission,
-
- 5. Use the Software for commercial purposes without our permission,
-
- 6. Sublicense, lease, rent, sell, distribute, or otherwise dispose
- of the Software without our written permission.
-
- This license is effective from the date of first use of the Software and
- shall remain in force until terminated. You may terminate this agreement
- by destroying any and all copies of the Software and its documentation.
-
-
- Parallel Port Information System Page 52
- ---------------------------------------------------------------------------
-
- Parallel Technologies, Inc. may terminate this agreement if you fail to
- comply with any of the terms and conditions of it. You agree to destroy
- any and all copies of the Software and its documentation, in whatever
- form, if we terminate this license agreement, and you agree to provide
- us written certification of such destruction upon our request.
-
- Statement of Exclusion of Warranty
-
- ALL PRODUCTS DELIVERED PURSUANT TO THIS AGREEMENT ARE DELIVERED ON AN
- "AS-IS" BASIS AND PARALLEL TECHNOLOGIES, ITS DEALERS AND DISTRIBUTORS,
- EXPRESSLY DISCLAIM ANY AND ALL WARRANTIES OR CONDITIONS OF MERCHANTABLE
- QUALITY OR FITNESS FOR A PARTICULAR PURPOSE.
-
- Limitation of Liability
-
- PARALLEL TECHNOLOGIES DISCLAIMS ALL WARRANTIES RELATING TO THIS
- SOFTWARE, WHETHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY
- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- PURPOSE, AND ALL SUCH WARRANTIES ARE EXPRESSLY AND SPECIFICALLY
- DISCLAIMED. NEITHER PARALLEL TECHNOLOGIES NOR ANYONE ELSE WHO HAS
- BEEN INVOLVED IN THE CREATION, PRODUCTION, OR DELIVERY OF THIS
- SOFTWARE SHALL BE LIABLE FOR ANY INDIRECT, CONSEQUENTIAL, SPECIAL,
- PUNITIVE, OR INCIDENTAL DAMAGES OR DAMAGES DUE TO LOST PROFITS, DATA,
- OR INFORMATION ARISING OUT OF THE USE OR INABILITY TO USE SUCH
- SOFTWARE EVEN IF PARALLEL TECHNOLOGIES HAS BEEN ADVISED OF THE
- POSSIBILITY OF SUCH DAMAGES OR CLAIMS. IN NO EVENT SHALL PARALLEL
- TECHNOLOGIES' LIABILITY FOR ANY DAMAGES EVER EXCEED THE PRICE PAID FOR
- THE LICENSE TO USE THE SOFTWARE, REGARDLESS OF THE FORM OF CLAIM. THE
- PERSON USING THE SOFTWARE BEARS ALL RISKS AS TO THE QUALITY AND
- PERFORMANCE OF THE SOFTWARE. This warranty gives you specific rights
- and you may have other rights.
-
- This agreement shall be governed by the laws of the State of
- Washington and shall inure to the benefit of Parallel Technologies,
- Inc. and any successors, administrators, heirs and assigns. Any
- action or proceeding brought by either party against the other arising
- out of or related to this agreement shall be brought only in a STATE
- or FEDERAL COURT of competent jurisdiction located in King County,
- Washington.