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.

Por

Sarah Mitchell

Publicado em

September 9, 2026

Última atualização em

September 11, 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 equipment built for a phone line can keep working once that line is gone.

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, an ATA lets old fax machine hardware keep working by translating its signal for the new connection. It is the workaround people reach for 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 sends and receives faxes entirely over the internet, with no analog phone line, ATA, or fax machine anywhere in the process. There is nothing to adapt because there is no analog signal to begin with, documents are sent from a browser, the mobile app, or email, and delivered to any standard fax number on the other end.

A Common Case: Retiring an Old Office Fax Line

A small law firm in Texas moves its office phone service to VoIP and initially buys an ATA just to keep its old fax machine working on the new line. Switching the firm's fax number to Fax.Plus instead removes the ATA, the phone line, and the machine from the setup entirely, the fax number keeps working through the browser and mobile app.

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. Fax tones often struggle over compressed VoIP audio, which is why analog fax equipment connected through an ATA can drop pages or fail to connect. Fax.Plus avoids this problem entirely since it sends faxes over the internet directly, with no analog signal or ATA involved.

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