System information

Troubleshooting Dialin Connections 16-369

Dialin: Modem Does Not Disconnect Properly

Symptom: Modem does not disconnect properly. Connections to the modem do not terminate when

the quit command is entered.

Table 16-12 outlines the problems that might cause this symptom and describes solutions to those

problems.

Table 16-12 Dialin: Modem Does Not Disconnect Properly

Possible Causes Suggested Actions

Modem is not sensing DTR Enter the Hangup DTR modem command string. This command tells the

modem to drop carrier when the DTR signal is no longer being received.

On a Hayes-compatible modem the &D3 string is commonly used to

conﬁgure Hangup DTR on the modem, as shown in Figure 16-1. For the

exact syntax of this command, see the documentation for your modem.

Modem control is not enabled on the

router or access server

Step 1 Use the show line exec command on the access server or router. The

output for the auxiliary port should show inout or RIisCD in the

Modem column. This indicates that modem control is enabled on the

line of the access server or router.

For an explanation of the show line output, see the “Using debug

Commands” section earlier in this chapter.

Step 2 Conﬁgure the line for modem control using the modem inout line

conﬁguration command. Modem control is now enabled on the

access server.

Note: Be certain to use the modem inout command instead of the

modem ri-is-cd command while the connectivity of the modem is in

question. The latter command allows the line to accept incoming

calls only. Outgoing calls will be refused, making it impossible to

establish a Telnet session with the modem to conﬁgure it. If you

want to enable the modem ri-is-cd command, do so only after you

are certain the modem is functioning correctly.