As always, the Cisco Web site has a wealth of information about configuring asynchronous connections and modems. The Cisco Modem-Router Configuration Guide, which includes detailed information on configuring the router to access a modem, appears at http://www.cisco.com/en/US/tech/tk801/tk36/technologies_tech_note09186a008009428b.shtml.
A list of specific modem-router configuration examples appears at http://www.cisco.com/en/US/tech/tk801/tk36/tech_configuration_examples_list.html.
Detailed instructions on manipulating the modemcap database, and which initialization strings you can use with which modems, appear on the Cisco Web site at http://www.cisco.com/en/US/tech/tk801/tk36/technologies_tech_note09186a008009491b.shtml.
You can view a comprehensive list of the standard AT commands for external analog modems by visiting http://www.cisco.com/en/US/products/sw/accesssw/ps4455/prod_command_reference09186a00800f48f6.html.
As always, the Cisco Web site has a wealth of information about configuring asynchronous connections and modems. The Cisco Modem-Router Configuration Guide, which includes detailed information on configuring the router to access a modem, appears at http://www.cisco.com/en/US/tech/tk801/tk36/technologies_tech_note09186a008009428b.shtml.