Troubleshooting
B-5
3920-A2-GN31-30
November 1996
Table B-5
(2 of 2)
Modem — VF Connection
Symptom
Action
Intermittent disconnects, high error
rates, or excessive retransmissions
occur.
Perform an End-to-End test. Refer to
Pattern located in the Test Branch section
of Chapter 3.
The modem establishes and then
disconnects the call.
You may have a poor VF connection. Try dialing again.
The remote modem may have encountered an error control (EC) disconnect. If
the modems cannot negotiate EC, then a disconnect occurs.
The remote modem may be in a forced Error Control mode (disconnect if there
is no error control). Reconfigure your modem to V.42/MNP or Buffer and try
again.
Check the LCD to determine the reason for the disconnect.
Perform a Local Analog Loopback test.
High error rates occur when running
a local loopback or self-test.
Incoming rings can cause data errors during a loopback test. Abort the test,
disconnect the modular VF cord, and restart the test.
Table B-6
Online Operation
Symptom
Action
The data is scrambled.
Verify that the character format (data bits, parity, and stop bits) is set to the
same value in both modems.
Data is missing during a transfer.
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 B-7
Mux Operation
Symptom
Action
The MUX configuration option does
not appear under DTE Interface.
The Dial Access Security feature is enabled. Verify that both the Answer and
Originate security options are disabled. Refer to sections
Set Answer Sec and
Set Orig Sec in Chapter 6.
The Dial Line Rate or LeasedLine Rate configuration option is set to an invalid
modulation. Refer to the
Dial Line or Leased Line configuration option in the
Multiport Mode section of Chapter 4 for the valid rates.
