Paradyne COMSPHERE 3821Plus User Manual page 122

COMSPHERE 3821Plus Modem
Symptom
Data scrambled or
unreadable
Missing data during a
transfer transfer
Symptom
Modems do not train-up on
leased lines
Symptom
Modem does not accept or
echo back AT commands
Modem does not accept or
echo back AT commands echo back AT commands
C-2
Table C-2
Online Operation
Verify that the character format (data bits, parity, and stop bits) is set to the same value in
both modems.
Verify that you are using the same method of flow control for both the modem and the DTE.
If using XON/XOFF flow control, verify that the modem's parity matches the DTE's parity.
Table C-3
Leased-Line Operation
Verify that the correct cabling is used for your application. Refer to
installation instructions.
Verify that one modem is configured for Answer mode and the other is configured for
Originate mode.
Table C-4
Modem – DTE Connection
Verify that the cable between the Async port of the DTE and the modem is a standard
RS-232 cable. If the cable is bad, replace it. (Null modem cables, also known as crossover
cables, do not work in this application.)
Using the SDCP, reload the Async Dial factory configuration area to guarantee that all
configuration options are returned to their proper setting.
If an SDCP is not available, use the AT command recovery technique in
Make sure that all AT commands are terminated with a carriage return.
Verify that the DTE has a valid character format. Valid format consists of 8 data bits with no
parity or 7 data bits with even, odd, mark or space parity.
Verify that the DTE's data rate is set to a level supported by the modem
(115,200 bps–300 bps).
If using a PC, verify that the modem is attached to the correct communications port.
February 1998
Action
Action
Chapter 2
Action
for modem
Chapter 4.
3821-A2-GB20-30