What is an analog telephone adaptor and how does it work?

An analog telephone adapter (ATA) provides an interface that allows you to use a standard telephone to communicate over an IP network such as the Internet. The name "analog telephone adapter" was originated by Cisco for their adaptor and other manufacturers may use slightly different acronyms, but essentially they mean the same thing.

An ATA-type device is a kind of computer that handles all of the tasks related to providing a telephone-line experience while talking over an IP network. This includes providing the dial tone, understanding touch tones, authenticating to the VoIP provider, encoding your voice in a way that allows it to be transmitted over an IP network, decoding IP packets into voice, etc. The ATA-type device will typically have a web server that will allow you to configure the device on your computer.

Depending on whether the device is provided with a service provider (pre-configured) or purchased from somewhere else, that web configuration may or may not be accessible or portions of the configuration may be restricted. Many US based VoIP service providers supply the ATA free of charge if you sign up for a monthly contract.

Please note: A deactivation fee is charged if your service is terminated if you use the VoIP providers service for less than 12 months. Most contracts are on a 30 day termination notice. Others charge you a once off fee (US$80 – US$150) for the ATA.