ATA means analog telephone adapter and is a device used as an interface between the analog telephone system and a digital network such as VoIP.
An ATA looks like an electrical panel with a power cord, an Ethernet port and a number of analog telephone ports with a currency exchange link typically called FXO. Since there are many analog ports, the user can connect more than one phone to a single analog adapter, so there is no need to change the VoIP settings.
ATA is often blocked and cannot be used with other service providers. The user can change the configuration only to a certain extent. Some of these don’t provide any blocking and these can be used with similar service providers. This service is generally offered by telephone and broadband telephone companies at cheaper telephone rates than conventional telephones.
It consumes about 3 to 5 watts of electricity and cannot operate without electricity. If the DC power fails, the ATA automatically switches to the analog telephone system. This is done to ensure that there is no loss of communication in companies that could be deadly.