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- COURIER HIGH SPEED MODEMS
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- CHAPTER 8. QUERIES AND HELP SCREENS
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- USER INQUIRIES (In)
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- The Inquiry command has eight options.
- The most commonly used options display
- the following information:
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- ATI3 Call duration
- ATI4 Current settings
- ATI5 NVRAM settings
- ATI6 Link diagnostics summary
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- I0 The modem returns a 3-digit product
- code. If you have a problem and call
- USRobotics' Technical Support Depart-
- ment, you may be asked for this
- product code.
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- I1 The modem performs a checksum of its
- read only memory (ROM) and returns
- the result to the screen. This
- function is used only in factory
- testing. The modem should always
- read the same number.
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- I2 The modem performs a test of its
- random access memory (RAM) and
- returns either the OK (0) or ERROR
- (4) result code, followed by OK when
- the test is completed. You may want
- to use this command as a checkpoint
- if the modem appears to be
- malfunctioning.
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- I3 The modem returns the duration of the
- last call if set to K0. It displays
- the actual time if set to K1. See
- the description of the Kn command in
- Chapter 5.
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- Queries and Help Screens 8-1
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- COURIER HIGH SPEED MODEMS
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- I4 The modem displays its current
- configuration. Figure 8.1 on the
- following page is an example.
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- 8-2 Queries and Help Screens
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- COURIER HIGH SPEED MODEMS
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- Figure 8.1ΩSample Result of ATI4 Command
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- I5 The modem displays the configuration
- stored in nonvolatile random access
- memory (NVRAM), as in the following
- example.
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- Figure 8.2ΩSample NVRAM Settings Screen
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- Queries and Help Screens 8-3
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- COURIER HIGH SPEED MODEMS
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- I6 During a connection, the modem
- monitors and stores information about
- link operations. When the call is
- ended, you can request a diagnostic
- summary, as in the following example.
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- Figure 8.3ΩSample Link Diagnostics Screen
- (ATI6)
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- For calls under data compression, the
- number of characters sent may be less
- than the number of octets sent, due to
- buffering operations. Line Reversals
- only applies to HST-mode operations,
- when the modems switch the high and low
- speed channels. At this time, online
- fallback is only reported Enabled in HST
- mode.
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- Most terms used in the display are self-
- explanatory except for the following:
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- Octets: Compressed data units. If the
- number of octets is greater than the
- number of characters sent, the modems
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- 8-4 Queries and Help Screens
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- COURIER HIGH SPEED MODEMS
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- probably used MNP5 compression on an
- already compressed file, and the result
- was expanded data.
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- Line Reversals: The number of times
- HST-mode modems switched the high and
- low speed channels.
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- Blers: Errors in data and protocol
- blocks. If there were many block
- errors, your receiver may have
- experienced problems on the line.
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- Blocks Resent: These represent blocks
- the remote modem resent due to the
- previous category, Blers.
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- Link Timeouts: Protocol detection
- problems: communications were severed
- momentarily, and the modems probably
- recovered. This does not indicate the
- retry timeout.
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- Link Naks: Negative acknowledgments
- (one or more blocks).
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- Data Compression: Indicates the type of
- data compression negotiated for the call
- (V42BIS or MNP5) or NONE. A V42BIS
- response includes the size of the
- dictionary and the maximum string length
- used, for example, 2048/32. See
- Appendix A for more information.
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- Equalization Long/Short: Status of S15
- bit 0; long if bit 0=0, short if bit
- 0=1. Short equalization applies only to
- HST modems.
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- Fallback: Enabled/Disabled: indicates
- whether or not the modems negotiated
- online fallback during the connection
- sequence.
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- Queries and Help Screens 8-5
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- COURIER HIGH SPEED MODEMS
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- Protocol: Indicates the error control
- protocol negotiated (LAPM, MNP, NONE) or
- SYNC for a synchronous call.
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- Speed: The last rates at which the
- receiver/transmitter were operating
- before disconnecting.
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- Disconnect Reason: Possible reasons the
- modem hung up are as follows:
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- DTR dropped: The DTE dropped the Data
- Terminal Ready signal, terminating the
- call.
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- Escape code: The operator sent the
- modem the +++ escape code.
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- Loss of carrier: The modem detected
- loss of the remote modem's carrier and
- waited the duration specified in
- Register S10 (default is 0.7 seconds).
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- Inactivity timeout: The modem
- detected no activity on the line for
- the duration specified in Register S19
- (default is 0, timer disabled).
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- MNP incompatibility: The modem is set
- to &M5 and the remote modem does not
- have MNP capability, or there was an
- MNP negotiation procedure error.
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- Retransmit limit: The modems reached
- the maximum of twelve attempts to
- transfer a data frame without error.
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- LD received: The remote modem sent an
- MNP error control Link Disconnect
- request.
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- DISC: The remote modem sent a V.42
- Disconnect frame.
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- 8-6 Queries and Help Screens
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- COURIER HIGH SPEED MODEMS
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- Loop loss disconnect: The modem
- detected a loss of current on the loop
- connecting it with the telephone
- company central office. This usually
- occurs because the remote modem has
- hung up: the central office drops
- current momentarily when there is a
- disconnect at the other end of a call.
- Unless Register S38 is set higher than
- zero, the modem immediately hangs up
- at loop loss.
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- Unable to Retrain: After several
- attempts, disturbances on the phone
- line prevented the modems from
- retraining, and they could no longer
- transmit or receive data.
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- Invalid speed: The modem is set to
- &N1 or higher, for a fixed link rate,
- and the remote modem is not operating
- at the same rate.
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- XID Timeout: The modems failed to
- negotiate the V.42 Detection (XID
- Exchange) phase.
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- SABME Timeout (Set Asynchronous
- Balance Mode Extended): The modems
- failed this part of V.42 link
- negotiation.
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- Break Timeout: Incompatible
- processing of a Break signal occurred.
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- Invalid Codeword: The modem received
- an invalid V.42 bis (compression)
- frame.
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- A Rootless Tree: The modem received
- an invalid V.42 bis (compression)
- frame.
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- Queries and Help Screens 8-7
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- COURIER HIGH SPEED MODEMS
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- Illegal Command Code: The modem
- received an invalid V.42 bis
- (compression) frame.
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- Extra Stepup: The modem received an
- invalid V.42 bis (compression) frame.
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- I7 The modem returns a product
- configuration. If you have a problem
- and call USRobotics' Technical
- Support staff, you may be asked to
- read this screen.
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- 8-8 Queries and Help Screens
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- COURIER HIGH SPEED MODEMS
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- S-REGISTER QUERY (Sr?)
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- This command allows you to view the
- contents of a particular S-Register, as
- in the following example that requests
- the contents of Register S0 ("On what
- ring will the modem answer?"):
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- ATS0? <Enter>
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- PHONE NUMBER QUERY (&Zn?)
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- At this command, the modem returns the
- phone number stored in NVRAM at position
- n, as in the following example that
- includes a sample modem response:
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- AT&Z3? <Enter>
- 5551234
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- LAST-DIALED NUMBER INQUIRY (DL?)
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- At this command the modem displays the
- number stored in the last-dialed number
- buffer:
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- ATDL?
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- HELP SCREENS
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- Courier modems provide four Help
- screens: summaries of the basic AT
- command set, extended ampersand (&)
- command set, S-Register functions, and
- Dial command options.
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- Stop/Restart Display
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- Queries and Help Screens 8-9
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- COURIER HIGH SPEED MODEMS
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- The following command stops the display.
- Hold down the Control key and type "S":
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- <Ctrl>-S
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- To restart the display, use the same
- command or press <any key>.
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- Cancel Display
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- Either of the following commands cancels
- the display.
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- <Ctrl>-C
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- <Ctrl>-K
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- 8-10 Queries and Help Screens
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- COURIER HIGH SPEED MODEMS
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- Basic Command Set ($)
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- At AT$, the Courier displays a screen
- that shows a partial summary of the
- command set. A second screen, activated
- by pressing any key, shows the remaining
- commands. The first screen is shown in
- Figure 8.4.
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- Figure 8.4ΩSample Basic Commands HELP Screen
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- Extended Command Set (&$)
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- At AT&$, the Courier displays a screen
- that shows a partial summary of the
- extended ampersand command set. A
- second screen, activated by pressing any
- key, shows the remaining command set.
- The first screen is shown in Figure 8.5.
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- Queries and Help Screens 8-11
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- COURIER HIGH SPEED MODEMS
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- Figure 8.5ΩSample Ampersand Commands HELP
- Screen
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- Dialing (D$)
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- At ATD$, the Courier displays this Dial
- command summary:
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- 8-12 Queries and Help Screens
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- COURIER HIGH SPEED MODEMS
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- Figure 8.6ΩSample Dial Command HELP Screen
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- Queries and Help Screens 8-13
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- COURIER HIGH SPEED MODEMS
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- S-Register Functions (S$)
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- At ATS$, the Courier displays a screen
- that shows a partial summary of the S-
- Register functions. A second screen,
- activated by pressing any key, shows the
- remaining registers. The first screen
- is as follows.
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- Figure 8.7ΩSample S-Register HELP Screen
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- 8-14 Queries and Help Screens
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