Analog telephone adapter

An analog telephone adapter (ATA) is a device for connecting traditional analog telephones, fax machines, and similar customer-premises devices to a digital telephone system or a voice over IP telephony network.

An ATA is often built into a small enclosure with an internal or external power adapter, an Ethernet port, one or more foreign exchange station (FXS) telephone ports. Such devices may also have a foreign exchange office (FXO) interface for providing alternative access to traditional land line telephone service.