User guide

MultiModem ZPX User Guide 23
in minutes the modem will wait before disconnecting when no data is sent or received. The Inactivity
Timer can be changed using AT Command \Tn, or register S30.
The modem cannot connect when answering
• Auto-answer maybe disabled. Turn on auto-answer in your data communications program or send the
command ATS0=1 to your modem interminalmode.
File transfer appears slower than it should
• If you are using a slow transfer protocol, such as Xmodem or Kermit, 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
ensure accuracy. You must have a clean line for maximum speed.
• If you are downloading a file compressed 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.
Data is being lost
• If you are using data compression, be sure the serial port baud rate is set to a minimum of four
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 &Kn and \Qn.)
• Try entering the &V (View Parameters) command, making a screen print of the diagnostics listing,
and checking for parameters that may be unacceptable.
Garbage characters display on the monitor
• Your computer and the remote computer may be set to different word lengths, stop bits, or
parities. If you are attempting to connect at 8-N-1, try changing to 7-E-1, or vice-versa, using your
communications software.
• You may be experiencing line noise. Enable error correction if it is disabled. Or, hang up and call
again; you may get a better connection.
• At speeds above 2400 bps, the remote modem may 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 &V (View Parameters) command, making a screen print of the diagnostics listing,
and checking for parameters that may be unacceptable.
Fax and data software won’t run at the same time
• You can have Windows compliant data and fax communication applications open at the same time,
but they cannot use the same modem at the same time. Make sure no other communications
application is open when you try to dial out. If you are using legacy communications software with
Windows, you may get a message that another application is occupying the device even when no
call is in progress. Close any open legacy communications programs and try again.
Chapter 4 -Troubleshooting