Disconnect Problems - AT&T DataPort PCX Modem User Manual

Troubleshooting
P: Your modem answers, but does not connect.
S: Make sure that the modem is configured for Automode
(ATF0). This allows the modem to connect to any modem
that recognizes CCITT V.32bis, V.32, V.23, V.22bis, V.22,
V.21, and Bell 212A and 103J modulation schemes. The
DataPort PCX modem does not support other vendors'
proprietary modulation schemes.
S: Determine the originating modem's modulation scheme,
and then use ATFn (select modulation) to force your
modem to operate at the same modulation scheme as the
originating modem.
S: To test your modem's hardware, perform a Local Analog
Loopback test (AT&T1) and verify that data entered at the
computer is echoed back to the computer. Before starting
the test, disable Error Control mode using either the AT\N0
or AT\N1 command. Issue the AT&T1 command, and begin
to enter data from your keyboard. It should appear on your
monitor. To stop the test, escape to command mode (+++)
and issue the AT&T0 command.

Disconnect Problems

P: Your modem dials and connects with another modem,
but after a moment, disconnects the call.
S: Your modem might be trying to communicate with an older
modem that does not support error control. (This is known
as an error control disconnect, where the modem is
configured to establish a call using error correction. If the
modems cannot negotiate error control, then a disconnect
occurs.)
Disable error control in your modem by entering an AT\N0
command. This places your modem into Buffer mode, a
non-error control mode. Try dialing the number again.
To restore error control to your modem, turn your modem
off and on.
S: You may have a poor telephone line connection. Try dialing
again.
Issue 2 July 1995
6-5