Information Technology Reference
In-Depth Information
Using the modem autoconfigure Command
If you are using Cisco Internetwork Operating System (Cisco IOS) Release 11.1 or later, you can
configure your Cisco router to communicate with and configure your modem automatically.
Use the following procedure to configure a Cisco router to automatically attempt to discover what kind
of modem is connected to the line and then to configure the modem:
1.
To discover the type of modem attached to your router, use the
modem autoconfigure discovery
line configuration command.
2.
When the modem is successfully discovered, configure the modem automatically using the
modem
autoconfigure type
modem-name
line configuration command.
If you want to display the list of modems for which the router has entries, use the
show modemcap
modem-name
. If you want to change a modem value that was returned from the
show modemcap
command, use the
modemcap edit
modem-name attribute value
line configuration command.
For complete information on the use of these commands, refer to the Cisco IOS documentation
Dial
Solutions Configuration Guide
and
Dial Solutions Command Reference
.
Do
not
put
&W
in the modemcap entry used for the autoconfigure. Having the NVRAM
rewritten every time a modem autoconfigure is done will destroy the modem.
Note
Establishing a Reverse Telnet Session to a Modem
For diagnostic purposes, or to initially configure the modem if you are running Cisco IOS Release 11.0
or earlier, you must establish a reverse Telnet session to configure a modem to communicate with a Cisco
device. As long as you lock the speed of the data terminal equipment (DTE) of the modem (see Table
16-5 for information on locking the modem speed), the modem will always communicate with the access
server or router at the desired speed. Be certain that the speed of the Cisco device is configured before
issuing commands to the modem via a reverse Telnet session. (See Table 16-5 for information on
configuring the speed of the access server or router.)
To configure the modem for a reverse Telnet session, use the line configuration command
transport
input telnet
. To set up a rotary group (in this case on port 1), enter the line configuration command
rotary 1.
Placing these commands under the line configuration causes the IOS to allocate IP listeners
for incoming connections at port ranges starting with the following base numbers:
2000 Telnet protocol
3000 Telnet protocol with rotary
4000 Raw TCP protocol
5000 Raw TCP protocol with rotary
6000 Telnet protocol, Binary Mode
7000 Telnet protocol, Binary Mode with rotary
9000 XRemote Protocol
10000 XRemote Protocol with rotary
To initiate a reverse Telnet session to your modem, perform the following steps:
