ATA (Analog Telephone Adapter): Explained

An ATA converts a phone line's analog signal for use with an internet-based system, the piece of hardware Fax.Plus's cloud faxing skips entirely.

Sarah Mitchell

Published on

September 9, 2026

Last updated on

November 3, 2026

An Analog Telephone Adapter (ATA) converts a traditional analog phone line signal so it can travel over an internet connection or VoIP system.
ATAs are commonly used to keep an old fax machine or landline phone working after switching to VoIP or fiber internet.
Fax.Plus sends and receives faxes over the internet directly, with no analog phone line, ATA, or fax machine required on the user's end.

What Is an ATA (Analog Telephone Adapter)?

An Analog Telephone Adapter (ATA) is a small hardware device that converts the analog signal used by traditional phones and fax machines into a digital format an internet or VoIP connection can carry, and back again. It sits between the analog device and the internet line, acting as a bridge so compatible analog equipment can work with a supported VoIP service. Fax compatibility depends on the device, provider and configuration and requires testing.

Why an ATA Matters for Faxing

A traditional fax machine expects a direct analog phone line. When a business switches to VoIP or drops its landline, a compatible, correctly configured ATA may let old fax machine hardware keep working by translating its signal for the new connection. It is one option people assess when they want to keep old telefax hardware running on a network it was never built for. For a closer look at how those tones get established between two devices in the first place, see how a fax modem works. The specific fax modem class a device supports still matters for the analog signal an ATA has to pass through cleanly.

Fax.Plus Needs Neither

Fax.Plus lets users send and receive online with no analog fax line, ATA or fax machine required at their location. Documents can be prepared through supported web, mobile or email workflows. The recipient can still use a traditional fax machine, and delivery can involve a telephone-network leg.

When replacing an existing office fax line, follow the guide to retiring an office fax adapter to plan the number, connected equipment and tests before cancelling the current service.

A Common Case: Retiring an Old Office Fax Line

Consider a small law firm in Texas moving its office phone service to VoIP. It assesses whether its provider and a compatible, correctly configured ATA can support the old fax machine and tests that route. If it instead chooses Fax.Plus, it checks number eligibility, tests browser or mobile faxing and keeps the current service active until transfer is confirmed complete. It removes only equipment and service no longer needed for fax, preserving any voice or other dependencies.

FAQs

Do I need an ATA to send a fax online?

No. An ATA is only needed to keep an analog device, like an old fax machine, working after a phone line is replaced by VoIP or fiber. Fax.Plus sends faxes over the internet directly, so no ATA, phone line, or fax machine is required.

Is faxing reliable over an ATA and VoIP connection?

Not always. Compatibility depends on the VoIP service, adapter and fax device, so test sending and receiving. Fax.Plus users do not need an ATA at their location.

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