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8 Solving Problems
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MultiModemZBA-V-V92 User Guide
The Modem Cannot Connect When Answering
Ö 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 Chapter 4. For information on changing the modem’s default configuration,
see “Step 6: Install and Configure Your Software” in Chapter 2.
Ö 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
Ö If you are using a slow transfer protocol, such as Xmodem, try Zmodem or Ymodem/G instead.
Ö 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.
Ö 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.
Ö 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.
Ö 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.
Ö 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
Ö 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.
Ö Make sure the flow control method you selected in software matches the method selected in the
modem. If you are using the modem with a Macintosh, you might have the wrong cable for
hardware flow control.
Ö 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.