Multitech MULTI MODEM II MT5600BA - Manual (Page 83)

8 Solving Problems
77
MultiModemII User Guide
Data Is Being Lost
4 If you are using data compression and a high speed serial port, set the serial port
baud rate to four times the data rate.
4 Your UART might not be reliable at serial port speeds over 9600 bps or 19,200
bps. Turn off data compression, reset your serial port speed to a lower rate, or
replace your serial port with a faster one.
4 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.
4 If you are running under Windows 3.1 and have a 16550AFN UART, you might
need to turn on the 16550’s data buffers and/or replace the Windows serial driv-
er, COMM.DRV.
4 Try entering the &V1 command 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
4 Your computer and the remote computer might be set to different word lengths,
stop bits, or parities. If you have connected at 8-N-1, try changing to 7-E-1, or
vice-versa, using your communication software.
4 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.
4 At speeds above 2400 bps, the remote modem might not use the same transmis-
sion 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.)
4 Try entering the &V1 command to display information about the last connection,
making a screen print of the connection statistics, and checking for parameters
that might be unacceptable.
The Modem Doesn’t Work with Caller ID
4 Caller ID information is transmitted between the first and second rings, so if
autoanswer is turned off (S0=0) or if the modem is set to answer after only one
ring (S0=1), the modem will not receive Caller ID information. Check your ini-
tialization string, and if necessary change it to set the modem to answer after the
second ring (S0=2).
4 Make sure that you have Caller ID service from your telephone company.