2.3 Modem Configuration
2.3.6 Modem capability database

The modem capability database (modemcap) is a list of modems with a known set of AT configuration commands for setting the attributes for each modem type. For example, many modems use the string AT&F to reset the modem to its factory default attributes.

Modem attributes have a full name and a two or three letter abbreviation. Factory default, for example, is also referred to as FD. For normal operation, you do not need to know these abbreviations. If you are familiar with the modem abbreviations, you can add entries to the modemcap database.

The modemcap database contains entries for supported modems. You can do the following tasks to manage a modemcap database entry:

  • View modem entries in the modemcap database with the show modemcap command.

  • View the contents of the modemcap entry of a modem.

  • Modify the modemcap entry of a modem.

  • Create a modem database entry.

As shown in Figure , the show modemcap command displays the modems in the modemcap database. In addition, with the modem type specified, it shows a complete list of the modemcap entries of the specified modem that includes the following fields:

  • Command description

  • Command abbreviation (with colon separator)

  • Command string

The command show modemcap codex_3260 shows the AT command string attributes and their values for the Codex 3260 modem, as shown in Figure .

The default modem type has modemcap values for a few of the most common attributes. It does not contain strings for attributes that vary widely by modem type, such as locking speeds, setting hardware flow control, or dealing with compression and error correction.

You can use the modemcap entry modem_name command or the show modemcap modem_name command to see the contents of the modemcap entry of a modem. The modemcap entry modem_name command displays modemcap values in a truncated form.

As you will see later in this section, you can also create variant modemcap entries to add new modems or to extend the functionality of a modem in the modemcap database.