5 Troubleshooting
26
MultiModemZPX User Guide
•
If you were online with a commercial online service, it may have hung up because of lack of
activity on your part or because you exceeded your time limit for the day. Try increasing the
length of time in minutes the modem will wait before disconnecting when no data is sent or
received. The Inactivity Timer can be changed using AT Command
\T
n,
or register
S30
.
The modem cannot connect when answering
•
Auto-answer may be disabled. Turn on auto-answer in your data communications program or
send the command
ATS0=1
to your modem in terminal mode.
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
&K
n
and
\Q
n
.)
•
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.
