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TROUBLE SHOOTING
This chapter provides information on the most commom problems, the possible causes, and the best solutions.
The modem does not respond to AT commands.
Conflict of COMx: port setting with another device.
Change the COMx: port of the Internal FaxModem
56K to a free port. Be sure to update your software
COMx: port setting as well.
The modem does not execute the command line.
Make sure you are typing 'AT' at the beginning of command line.
Make sure the modem is not in Data Mode. type +++ if necessary.
Make sure your software is set to the same COMx: port as the modem is.
The modem does not give a response after an AT command was executed.
The echo and/or responses may be turned off by the
ATE0Q1 commands.
Use AT&V to check that.
Use ATE1Q0 then Enter to change them back.
Make sure the modem is in Command Mode rather than in Data Mode when you type the AT command.
The modem gives an 'ERROR' response after an AT command was executed.
Make sure you did not type an invalid command.
Make sure your command line is 40 characters or less in length.
The modem goes off-hook and disables the telephone line.
The modem may be set to auto-answer mode when it rings.
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Type ATS0=0, then Enter at the command line to disable the auto-answer mode.
The modem does not auto-answer the phone.
Make sure the software is configured to auto-answer the phone.
Type ATS0=n then press Enter. The n stands for the number of rings the modem will answer on.
The software does not control the modem properly or can not detect the modem.
Make sure the software has been set up correctly.
Check the initialization and dial strings.
Some TSRs (programs that stay in memory after they are loaded) may conflict with the communications software.
Restart your computer without loading any TSRs.
The characters on the screen are doubled.
Both the modem and the software have the echo feature turned on at the same time.
Turn off the software echo feature off.
The remote modem is echoing your typed characters.
Type ATE1 then Enter at the command line. Then turn off the software echo feature.
No text appears on the screen when in data mode.
The remote modem is not echoing your typed characters.
Type ATE0 then press Enter at the command line.
Then turn the software echo feature on.
Your software may not be set to use Full Duplex or the remote modem may not be set to use Full Duplex either.
C:The remote modem may be waiting for you to type a command before it will reply with text.
No text appears on the screen when in command mode.
If you can't see the characters you are typing, then type ATE1 then press Enter.
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The modem does not dial a phone number after you execute the AT dial command.
If you are using touch tone dialing on a phone line that requires pulses, then it may not work.
Use ATDT in place of ATDP.
When your communications software tells the modem to dial, it does not.
Make sure the software dialing prefix is ATDT.
Make sure the software and modem are set to the same COMx: port.
The modem may not have hung up the phone line since the last call.
Change to command mode and type ATH then press Enter.
When dialing another modem, you receive a
'CONNECT' response, but nothing else.
The remote modem may be waiting for you to type a command. Or try to press Enter for logging on to the remote site.
The modem speaker does not make any sound when you're connecting to another modem.
The software may have the speaker disabled.
Change the setting in your software or use the ATMn command to turn the speaker on.
The modem disconnects (looses the connection) in the middle of use.
The remote modem may have locked up.
The telephone switch may have disconnected your call.
Your software may have turned off the DTR signal.
The modem does not connect with another modem.
There may be a problem with the remote modem if you do not hear the high pitched tone from the remote modem.
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Occasionally, the modem gives a burst of errors.
The telephone line may be noisy or bad.
Hang up the call and try to connect again for getting a better telephone line.
If there are other telephones on the same line that your modem is using, someone may have picked up a telephone on that extension.
Your telephone line may have the call waiting feature.
Try adding '*70,' to your ATDT dialing command line.
If it doesn’t help, ask your telephone company how to disable it temporarily.
The modem gets errors in transmitted data randomly.
Try to use V.42 or MNP1-4 if possible.
Connect the modems at a slower baud rate.
After you download a file, it was not stored on your disk drive.
If both modems are using MNP or V.42 protocol, then the flow control may not be enabled.
Configure your software to use RTS/CTS flow control.
That will cause your computer to pause long enough for the file to be stored to disk.
The text on the screen is not legible.
Your software settings may not match the settings on the remote site.
Make sure your data bits, stop bits, and parity settings match the settings that the other computer is using.
The two most common settings are: 8 data bits, None parity, and 1 stop bit (8,N,1) or 7 data bits, Even parity, and 1 stop bit (7,E,1).
If the telephone line is very noisy, you may see corrupted data on your screen.
Due to poor telephone line conditions, the modem may have fallen back to a slower communication speed. You may need to change the baud rate setting in your software to match this slower speed. To return
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the modem to the higher speed, disconnect the link and re-establish again.
When using V.42bis or MNP5, some features are disabled.
You may be using a non-streaming protocol, like
Xmodem or Ymodem to transfer files. Those are fine unless you are using V.42bis or MNP5
When using V.42bis or MNP5, you should use a streaming transfer protocol like Ymodem-G or
Zmodem.
Configure your software to use hardware flow control
(RTS/CTS ON).
When the modem is connecting to another modem, it reports a higher connect baud rate that it is really using.
The modem defaults to report the modem-to-computer baud rate when it responds with CONNECT.
Go to command mode with your communication program (like Telix) and type ATW2, then press Enter.
This tells the modem to report the modem-to-modem baud rate instead.
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