MultiModemZPX User Guide | 4 Troubleshooting |
The Modem Cannot Connect When Answering
•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.
•The application should supply DTR. 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.
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.
•If you are downloading a compressed file with MNP 5 hardware compression enabled, try disabling data compression. The transfer may be marginally slower with data compression enabled, because hardware data compression cannot compress a file already compressed by an archiving program.
•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 greater than 33,600 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, set the serial port baud rate to two to six times the data rate.
•Make sure the flow control method you selected in your software matches the method selected in the modem (see AT commands &K and \Q.)
•Enter the I11 command in online mode to display information about the last connection. Then make a screen print of the connection statistics, and look for unacceptable parameters.
20
