2.3 Modem Configuration
2.3.8 Modem autoconfiguration

If you know that your modem can be configured by using an initialization string from one of the preconfigured scripts of the modemcap, you can issue the modem autoconfigure type command. With this command, type is one of the modemcap strings displayed in the "Modem Capability Database" section shown earlier in this chapter. If you list a specific modem type, initialization proceeds more quickly than if you let the autodiscovery take place. In the following example, the access server is configured to send an initialization string for a USR Sportster modem on line 1:

Router(config)#line 1
Router(config-line)#modem autoconfigure type usr_sportster

To eliminate the overhead of modem autodiscovery and to avoid modem configuration ambiguity caused by modem autodiscovery, configure the modem type by using the modem autoconfigure type command whenever possible.

With automatic modem configuration, each time a modem is reset, a chat-script is executed that sends a string of modem configuration commands (AT commands) to the modem. This modem configuration command string is generated automatically whenever the modem is recycled.

Speed Issues with Modem Autoconfiguration
Table shows the results of autoconfiguration tests that were performed on a router to determine how long it took the router to configure an attached modem.