Analog Terminal Cards (ATCs) and single-port Analog Terminal Adapters (ATAs) enable you to connect analog devices such as 2500-series telephones and fax machines to a system.

The ATA window displays information for both ATC ports and ATAs. The ATA list shows each device sorted by extension. An asterisk in front of the extension identifies devices associated with the default user profile, New User, which is automatically associated with new telephones during Auto Discovery.

You can not use an ATA for high speed Fax machines or any kind of modem.  An ATA is best used with cordless analog type phones.