Motorola V3229 - 14.4 Kbps Modem Specifications download pdf (Page 206)

Configuring and Managing External Modems

Modem Troubleshooting Tips

DC-152

Cisco IOS Dial Technologies Configuration Guide

Modem Troubleshooting Tips

Table 14 contains troubleshooting tips on modem access and control.

Table 14 Modem Troubleshooting Tips

Problem Likely Cause

Connection refused. Someone already has a connection to that port.

an EXEC is running on that port.

The modem failed to lower the carrier detect (CD) signal after a call

disconnected, resulting in an EXEC that remained active after disconnect.

To force the line back into an idle state, clear the line from the console

and try again. If it still fails, ensure that you have set modem inout

command for that line. If you don't have modem control, either turn off

EXEC on the line (by using the exec-timeout line configuration

command) before making a reverse connection or configure the modem

using an external terminal. As a last resort, disconnect the modem, clear

the line, make the Telnet connection, and then attach the modem. The

prevents a misconfigured modem from denying you line access.

Connection appears to hang. Try entering “^U” (clear line), “^Q” (XON), and press Return a few times

to try to establish terminal control.

EXEC does not come up; autoselect is on. Press Return to enter EXEC.

Modem does not hang up after entering quit. The modem is not receiving DTR information, or you have not set up

modem control on the router.

Interrupts another user session when you dial in. The modem is not dropping CD on disconnect, or you have not set up

modem control on the router.

Connection hangs after entering “+++” on the

dialing modem, followed by an ATO.

The answering modem saw and interpreted the “+++” when it was echoed

to you. This is a bug in the answering modem, common to many modems.

There may be a switch to work around this problem; check the modem’s

documentation.

Losing data. You may have Hardware Flow Control only on for either the router’s line

(DTE) or the modem (DCE). Hardware Flow Control should be on for

both or off for both, but not for only one.

Using MDCE. Turn MDCE into an MMOD by moving pin 6 to pin 8 because most

modems use CD and not DSR to indicate the presence of carrier. You can

also program some modems to provide carrier info via DSR.

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Motorola V3229 - 14.4 Kbps Modem Specifications Page 206