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Text File | 1990-09-12 | 18.9 KB | 410 lines

TeleReplica Instruction Manual 1. What TeleReplica Will Do 1.1 TeleReplica will allow you to connect two IBM PC-compatible computers together via telephone lines and modems, and arrange for input to be accepted from either keyboard, and for both displays to appear identical. The computer which is running normal programs is called the host computer. The other computer is called the replica computer, since its display is a replica of the host computer's display. 1.2 TeleReplica will do a reasonable job of optimizing the screen changes transmitted, so that (for example) moving a highlighted menu bar will appear almost immediately even at 1200 baud (provided the call is relatively local). 1.3 TeleReplica always updates the replica computer's screen to match the current host screen. This means that if several commands are issued without waiting for the display to catch up, then the replica screen will be updated to show the final host screen, without wasting time transmitting the intermediate screens. 1.4 TeleReplica uses a password of up to 39 characters, which means an intruder would (on average) take millions of years at 2400 baud to guess a well chosen password! Since this password is transmitted automatically, there is no need to keep it short and easy to remember - once TeleReplica is installed, you will never need to enter the password manually. 1.5 TeleReplica will allow the host site to call the replica site, or the other way around. For consultants this means you can make your clients pay the telephone bills! 1.6 TeleReplica will automatically detect the baud rate being used by the replica computer, and set the host computer's baud rate to match. This means that users with different speed modems can all access a single host. 1.7 TeleReplica only uses about 8K of memory on the host computer, which means there should be enough memory left to run most applications. 2. What TeleReplica Will NOT Do 2.1 TeleReplica will not replicate graphics displays. If the user at the replica computer runs a program that displays graphics, then the replica display may show (textual) garbage. Keystrokes will still be transmitted to the host computer, but the user must remember which keys are necessary to get out of graphics mode again! TeleReplica gives a warning that graphics mode has been entered, but by then it is too late to avoid it. However, in an emergency TR can instruct the host computer to reboot, so provided TRHOST is run from AUTOEXEC.BAT this provides a means of recovery. 2.2 TeleReplica will only work with standard COM1 or COM2 ports. Use of COM3, COM4, and all PS/2 ports is not supported. 2.3 TeleReplica will only work with a modem and modem cable that provide carrier detect and data terminal ready signals in addition to the minimum transmit data, receive data and ground signals. 2.4 TeleReplica will cause bad "snowing" on some older CGA display cards. No attempt has been made to use the retrace intervals for screen memory access. 2.5 TeleReplica will slow down the normal operation of the host computer. On a 4.77MHz PC performance can be halved; on a faster host the difference will not be so noticeable. 3. Why Use TeleReplica? 3.1 Access to Local Area Network from Home TeleReplica will allow you to connect into your office computer from home. This means you do not need to take all your data files home with you, and that you do not need to license additional copies of your software (since your home computer is not running the software, only replicating the screen of your office computer). If your office computer is part of a local area network, then you automatically have access to all the network facilities from home. 3.2 Software Support TeleReplica will allow you to take over your client's computer, so that you can see what is going wrong. In many cases this will avoid the need for an expensive trip to the client's site. 4. How to Install TeleReplica 4.1 Host Installation To install TeleReplica at the host computer, first copy the files: TRHOSTIN.EXE, TRHOST.EXE, TRPUT.EXE, TRGET.EXE, TRTALK.EXE, TRCHECK.EXE, TRKEY.EXE and TRDIAL.EXE into a directory (say \TR) on the host computer. Then enter the command: TRHOSTIN Your display should show a menu similar to: TeleReplica Host Installation Program 0. Save changes and leave installation program 1. Select serial port (currently COM1) 2. Change password (currently "password") 3. Change modem initialization string (currently: "\ratz\r\D1000.ata\r") 4. Change modem dialing format string (currently: "atdt %s\r") 5. Select maximum baud rate (currently 2400) 6. Abandon changes Selection: Consider each of these options in turn: 4.1.1 Select Serial Port Another menu will appear: TeleReplica Host Program Serial Port Selection 0. No change 1. COM1 port (base 0x03f8, interrupt 0x0c) 2. COM2 port (base 0x02f8, interrupt 0x0b) Selection: Only the two standard serial ports are currently supported. Simply choose one or the other! 4.1.2 Change Password The string editing menu will appear: TeleReplica Host Program Password Selection Edit existing string: password Whenever you see the Edit existing string: prompt, you can use the left and right arrow keys to move the cursor through the string, and the backspace and delete keys to delete characters to the left of or under the cursor respectively. Any normal characters you type will be inserted at the cursor position. You will not be able to enter more than the maximum allowed number of characters for any string. Since you will only need to enter the password twice during installation, and never in normal use, it is recommended that you make the password near the maximum length and quite random. The main thing is that no-one should have any chance of guessing the password. 4.1.3 Change Modem Initialization String The string editing menu will appear again, this time asking for the modem initialization string. This string is transmitted to the modem at the maximum baud rate when TRHOST runs for the first time. If you are using an automatic power switch that powers up the host computer when the telephone starts ringing, then the initialization string may need to answer the phone. There may also be various operating modes that cannot be stored permanently in your modem's non-volatile memory, and which must therefore be established each time TRHOST starts. In many applications, where nothing needs to be changed, this string may be blank. You will probably need to refer to the instruction manual for the host modem to work out what if anything is required. As well as normal characters, you may need to include some special characters such as carriage return. Carriage return can be encoded as \r (see the main menu in section 4.1). Alternatively, any character can be entered in hexadecimal as \0x followed by two hex digits (for example, carriage return is \0x0D). It may also be necessary to include some kind of delay. For example, some modems go off into a world of their own for a second or so after a reset command. Delays are entered in milliseconds as \D followed by the delay (for example, \D1000. [1 second] or \D500. [half a second]). Delays are only accurate to the nearest 1/18th of a second, so the number you enter may be modified slightly to reflect the nearest possible actual delay. 4.1.4 Change Modem Dialing Format String This string determines what TRDIAL will send to the modem to dial a number. The usual use of TRDIAL will be something like TRDIAL 221166, so normally the dialing format string should contain a %s to insert the number. For example, if the dialing string is "atdt %s\r" and the user enters the previous dialing command, then what will be sent to the modem is "atdt 221166\r". Alternatively, if only one number is required, then the dialing format string may contain the actual number, in which case the user will only need to enter TRDIAL by itself. 4.1.5 Select Maximum Baud Rate Another window will appear: TeleReplica Host Program Maximum Baud Rate Selection Enter baud rate: You should enter the maximum baud rate that the host modem is capable of using. Usually this will be 1200, 2400 or 9600. Note that TRHOST can automatically adjust to half this baud rate, a quarter of this baud rate, or one eighth of this baud rate. Thus if you choose 2400 baud, TRHOST will be able to work at 2400, 1200, 600 or 300 baud (provided the host modem can handle these speeds). 4.1.6 Abandon Changes If you have made a mistake, or if you only wanted to see what the current settings were, then this option allows you to quit without making any changes. 4.1.7 Save Changes and Leave Installation Program This is the normal way to exit this program when you have made all the required changes. The relevant files (TRHOST.EXE, TRGET.EXE, TRPUT.EXE and TRDIAL.EXE) will all be modified appropriately. 4.2 Replica Installation To install TeleReplica at the replica computer, first copy the files: TR.EXE, TR.HLP, and TR.TR into a directory (say \TR). Then use a text editor (such as DTE) to edit the file TR.TR. This file should look something like: TeleReplica Configuration File Note: Do NOT change the order of these parameters, or delete any lines! "COM1" Communications port (COM1 or COM2) 2400 Baud rate (normally 300, 1200, 2400, or 9600) "COMSPEC" Path for DOS Command Interpreter (or "COMSPEC") 07 Attribute for normal text (such as help screen) 47 Attribute for file transfer monitoring [70 for Hercules] 4F Attribute for pop-up window text "trput %s\r" Host command to send (download) files "trget\r" Host command to receive (upload) files "trtalk\r" Host command to start "talk" session 440 Frequency of "bell" tone (Hz) 100 Duration of "bell" tone (ms) 128 Block size for file upload (1-256) 4 Number of block buffers for upload (1-8) "NO" Send "break" in response to framing error? (YES/NO) 111 Length of "break" (ms) 4000 Time to wait before giving up transfer (ms) 2000 Time to wait for first char before timeout (ms) 500 Time to wait for subsequent chars in block (ms) "password" Password to log in to host computer "atdt 123 456\r" Connect command for modem "\D1000.+++\D1000.ath0\r" Disconnect command for modem Each of the remaining lines must contain 3 strings and a number. The first string is the trigger string to search for. The second string is the response to be sent after the trigger. The third string is the response to be sent after timeout. The number is the time to wait before timeout (in ms). "RING" "ata\r" "" 10000 Most of these parameters will not need to be changed. The serial port (COM1 or COM2) and the baud rate should be set appropriately for the replica computer and modem. Video attributes are two hexadecimal digits: the first is the background color, and the second is the foreground color. The password must be changed to match the password installed in TRHOST at the host computer. The connect command for the modem is sent when TR starts running, and the disconnect command is sent when TR terminates. The modem command strings here have the same format as those described above for the host computer installation. However, make sure you leave the double quotes (") around each string! The automatic response strings at the end of the file can be used to respond to modem status messages. For example, if the replica computer's modem is not set to auto-answer, then TeleReplica may need to respond to a "RING" message from the modem by answering the 'phone. Please note that since this file contains the password, anyone who obtains a copy of this file can access the host computer! 5. How to Use TeleReplica The following instructions assume that TeleReplica has been correctly installed (see section 4). 5.1 Host Computer First run the TRHOST program. If the replica computer is to originate the telephone call, this is all that is necessary. If the host computer is to originate the call, then use the command: TRDIAL or TRDIAL number depending on how the dialing format string was installed. Once TRHOST is resident and the call is established, the host computer can be used normally. The only difference is that everything that appears on the screen is also being replicated on the replica computer's screen. The only way to remove TRHOST from memory is to reboot the host computer. 5.2 Replica Computer Use the command: TR [use TR.TR configuration file] or TR filename [use filename.TR configuration file] If the replica computer was to originate the call, then the modem initialization string in the configuration file will usually include a dial command to call the host computer. If the host computer was to originate the call, then the initialization string may contain an answer 'phone command. Note that in this case it is important that the TR program not be run until after the phone starts ringing! (Alternatively, there may be no initialization string, but instead there may be a trigger string to respond to RING from the modem.) If the configuration file contains no modem initialization string, then the user at the remote computer can enter modem commands manually. This may be convenient for a consultant wishing to dial many different clients. Once both TR and TRHOST are running and connected to each other, they will automatically adjust the host computer's baud rate and the host computer will check the password provided by the replica computer. Provided the password is correct, the replica computer will effectively be able to take over the host computer, or alternatively to observe whatever the host computer is doing. Any key typed on the replica computer will be acted upon by the host computer, and anything that appears on the host computer's screen will also appear on the replica computer's screen. It is sometimes necessary to execute a command on the replica computer, rather than transmitting the keystroke to the host computer. This is achieved by holding down left shift, right shift, ctrl and alt all at the same time. When you do this a list of all the possible commands will be displayed, and you can then type the required command key: F3 start a "talk" session, where what is typed at the host computer is displayed in the top half of the screen, and what is typed at the replica computer is displayed in the bottom half of the screen. This is useful for carrying on a "conversation" with the user at the other end. F4 end a "talk" session F8 reboot the host computer (useful if host computer "hangs" for any reason, but make sure TRHOST is run from AUTOEXEC.BAT!) F9 send break, restart session [use this if TeleReplica locks up - very rare!] F10 exit TeleReplica [optionally shell out and return later] Home refresh display from HOST [use this if a bad 'phone line messes up the screen] PgUp upload file using DMP protocol [transfer file(s) from replica to host] PgDn download file using DMP protocol [transfer file(s) from host to replica] Note that before starting a "talk" session or performing a file transfer, the host computer must be at the DOS prompt, and TRTALK.EXE, TRGET.EXE and TRPUT.EXE must be accessible in the current path. If a file transfer needs to access a file in another directory, it may be convenient to shell out of TR, change directories, and then exit from DOS back into TR to start the file transfer. However, TR will not transmit any drive or path that you specify. 6. TeleReplica Utility Programs 6.1 TRCHECK TRCHECK checks to see if the current time is within a specified range, and returns the DOS errorlevel set to 0 if within the range and 1 if outside the range. The following code might appear in an AUTOEXEC.BAT file on a host computer: trcheck 9:00:00 17:00:00 if errorlevel 1 goto runTR goto done :runTR trhost :done The effect of this is to first check to see if the time is between 9AM and 5PM. If so, then errorlevel is set to 0, and nothing further happens. However, if the time is not between 9 and 5, then trhost will be run. This has proved valuable when TRHOST must run on an office computer outside normal working hours, but the computer must be used normally during the day. 6.2 TRKEY TRKEY checks to see if a key has been pressed. This is useful when a computer will usually be used as a TeleReplica host, but sometimes must be used locally. Rather than having to boot from a different disk, the following code might appear in an AUTOEXEC.BAT file on a host computer: trkey if errorlevel 1 goto done trhost :done The effect of this is to run TRHOST only if no key has been pressed. If a user is at the computer and presses a key then TRHOST will not be loaded.