Chapter 7 - Troubleshooting
Modem Cannot Connect When Answering
The default DTR Control command (&D2) inhibits autoanswer. To enable autoanswer, change DTR Control to &D0, and make sure &Q0, &Q5, or &Q6 is also set. For more information, see the &D command in the AT Commands Reference Guide. For information on changing the modem’s default configuration, see “Install and Configure Your Software” in Chapter 2.
Autoanswer might be disabled. Turn on autoanswer in your communications program or send the command ATS0=1 (ATS0=2 if you have Caller ID service) to your modem in terminal mode.
File Transfer Is Slower Than It Should Be
If you are using a slow transfer protocol, such as Xmodem, try Zmodem or Ymodem/G instead.
Is your line noisy? If there is static on your line, the modem has to resend many blocks of data to insure accuracy. You must have a clean line for maximum speed.
Are you downloading a compressed file with MNP 5 hardware compression enabled? Since hardware data compression cannot compress a file already compressed by an archiving program, the transfer can be marginally slower with data compression enabled than with it disabled.
Does your Internet service provider (ISP) use the same 56K protocol as your modem? The default setting of your modem is to connect using either the V.92 or the V.90 protocol, depending on which one the ISP’s modem is using. If your ISP uses the V.90 protocol, the maximum speed you will be able to upload at is 33,600 bps. Check with your ISP to see which protocols it supports.
Are you trying to send a file to another client modem? If so, then your maximum possible connect speed is 33,600 bps. You can upload at speeds up to 48,000 bps only when connected to an ISP that supports the V.92 protocol.
Try entering the I11 command in online mode or the &V command in command mode to display information about the last connection, making a screen print of the connection statistics, and checking for parameters that might be unacceptable.
Data Is Being Lost
If you are using data compression and a high speed serial port, set the serial port baud rate to two to six times the data rate.
Make sure the flow control method you selected in software matches the method selected in the modem.
Try entering the I11 command in online mode or the &V command in command mode to display information about the last connection, making a screen print of the connection statistics, and checking for parameters that might be unacceptable.
There Are Garbage Characters on the Monitor
Your computer and the remote computer might be set to different word lengths, stop bits, or parities. If you have connected at
You might be experiencing line noise. Enable error correction, if it is disabled, or hang up and call again; you might get a better connection the second time.
At speeds above 2400 bps, the remote modem might not use the same transmission or error correction standards as your modem. Try connecting at a slower speed or disabling error correction. (With no error correction, however, line noise can cause garbage characters.)
Try entering the I11 command in online mode or the &V command in command mode to display information about the last connection, making a screen print of the connection statistics, and checking for parameters that might be unacceptable.
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