Specifications

DC-52
Cisco IOS Dial Technologies Configuration Guide
Overview of Modem Interfaces
This chapter describes modem interfaces in the following sections:
• Cisco Modems and Cisco IOS Modem Features
• Cisco IOS Modem Components
• Logical Constructs in Modem Configurations
See the chapter “Overview of Dial Interfaces, Controllers, and Lines” for more information about Cisco
asynchronous serial interfaces.
To identify the hardware platform or software image information associated with a feature, use the
Feature Navigator on Cisco.com to search for information about the feature or refer to the software
release notes for a specific release. For more information, see the “Identifying Supported Platforms”
section in the “Using Cisco IOS Software” chapter.
For a complete description of the modem support commands in this chapter, refer to the Cisco IOS
Modem Command Reference. To locate documentation of other commands that appear in this chapter,
use the command reference master index or search online.
Cisco Modems and Cisco IOS Modem Features
Deciding which asynchronous features to use, to some degree, depends on your hardware configuration.
All Cisco access servers must have their asynchronous interfaces and lines configured for network
protocol support. Commands entered in asynchronous interface mode configure protocol-specific
parameters for asynchronous interfaces, whereas commands entered in line configuration mode
configure the physical and logical aspects for the same port.
Modems inside high-end access servers need a localized modem country code. This code is projected
from the Cisco IOS software to the onboard modems using the modem country {mica |
microcom_hdms} country command. The following are high-end access servers: Cisco AS5800,
Cisco AccessPath, Cisco AS5300, and the Cisco AS5200.
Modems externally attached to low-end access servers need to receive initialization strings from the
modem autoconfigure discovery command. For troubleshooting tips, see the section “External
Modems on Low-End Access Servers” in the chapter “Configuring and Managing External Modems.”
The following are low-end access servers: Cisco AS2511-RJ, Cisco AS2509-RJ, Cisco 2509,
Cisco 2511, and the Cisco 2512.
Figure 12 shows a Cisco AS2511-RJ access server. Figure 13 shows a Cisco AS5300 access server.
Notice that modems are either inside or outside the chassis, depending on the product model.