How do I know if my ATA supports T.38?

Check the device specifications for T.38 support — it's usually listed under fax or codec settings. If it's listed, it should work with Power-T.38 SIP trunks. You can verify by signing up for a free trial and running our automated [ECM self-test](https://foip.t38fax.com/ecm-self-test) to confirm T.38 and ECM are active on your connection.

Do I need a specific ATA to fax over IP?

You need an ATA that supports the T.38 protocol — not all do. The Grandstream HT80x series, Cisco ATA 191/192 (MPP), and Poly ATA 400/402 are the most popular choices. All three are T38Fax-certified with step-by-step setup guides in our knowledge base.

Can I use my existing fax machine with T38Fax?

Yes. Most standard fax machines work with T38Fax when connected through a T.38-compatible ATA. Plug your fax machine into the ATA's FXS port, configure the ATA with your Power-T.38 SIP trunk credentials, and you're faxing over IP. Some Toshiba and Lexmark MFPs support T.38 natively and can connect without an ATA.

What if my device isn't on this list?

If your device supports T.38, it should work. Our interoperability team is constantly testing new hardware. [Contact us](/contact/) with your device model and we'll let you know, or sign up for a [free trial](https://my.t38fax.com/signup) and test it yourself — there's no risk.

Compatibility

T.38 Compatible Devices — Tested & Certified for Power-T.38

80+ devices tested and certified for Power-T.38 SIP trunks. Find your ATA, gateway, fax server, or fax machine and get a step-by-step setup guide.

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Overview

Will Your Device Work with T38Fax?

Our interoperability team has tested and certified over 80 devices for use with Power-T.38 SIP trunks — ATAs, gateways, fax servers, fax machines, and softswitches. Every device on this page has a step-by-step setup guide in our knowledge base.

If you’re looking for a T.38-compatible fax ATA adapter, trying to make your fax server work over a SIP trunk, or evaluating whether your existing hardware is ready for fax over IP — start here.

ATAs & Gateways

Analog Telephone Adapters (ATAs)

An ATA connects a standard fax machine to a SIP trunk. It’s the most common way to fax over IP without replacing your existing equipment. These are the T38Fax-certified ATAs we recommend and support.

Grandstream HT80x Series

The most widely deployed fax ATAs in our customer base. Affordable, reliable, and well-documented.

Grandstream HT801 V2 / HT802 V2 — 1 or 2-port FXS, 10/100 Mbps. Recommended for new installations.
Grandstream HT812 — 2-port FXS with gigabit router. Best choice when connecting two fax machines to one trunk.
Grandstream HT813 — 1-port FXS + 1-port FXO with gigabit router.
Grandstream HT814 — 4-port FXS with gigabit router.
Grandstream HT818 — 8-port FXS gateway with gigabit router.

Legacy models (HT701, HT801 V1, HT802 V1) are still certified but we recommend the V2 series for new deployments.

Cisco ATA 191 / ATA 192 (MPP)

The successor to Cisco’s widely-deployed SPA112/SPA122 line.

Cisco ATA 191-MPP — 2-port FXS, 100BaseT WAN.
Cisco ATA 192-MPP — 2-port FXS, WAN + LAN interfaces.

Important: Only the MPP (Multiplatform) variants are certified. Non-MPP models are designed for Cisco call control systems and do not work with third-party SIP trunks.

Poly ATA 400 / ATA 402

Poly ATA 400 / 402 — 1 or 2-port FXS. Current-generation Poly analog adapters.

Obihai / Polycom OBi Series

OBi200 — 1-port FXS with USB.
OBi202 — 2-port FXS with USB and router.
OBi302 — 2-port FXS with USB. One of our recommended two-port models.

AudioCodes

AudioCodes MediaPack MP11X — Cost-effective analog VoIP gateway for connecting fax machines and PBX systems.

Not sure which ATA to choose? We recommend the Grandstream HT812, Polycom OBi302, or Cisco ATA 192-MPP as our top three two-port options.

Fax Gateways

For organizations connecting multiple fax machines at a single site, an FXS gateway provides more ports and centralized management.

Grandstream GXW Series

Grandstream GXW4004 — 4-port FXS gateway.
Grandstream GXW4008 — 8-port FXS gateway.
Grandstream GXW4200 — High-density FXS gateway.

Fax Machines

T.38-Native Fax Machines

Some multifunction printers support T.38 natively — no ATA required. These devices connect directly to your network and register with your Power-T.38 SIP trunk.

Toshiba e-STUDIO Series — IP fax-capable MFPs that send and receive natively over T.38.
Lexmark MX611de
Lexmark MX410de

Most fax machines that aren’t T.38-native will still work with T38Fax when connected through a certified ATA. See our recommended fax machine settings for configuration guidance.

Fax Servers

Fax Servers & Appliances

T38Fax was built around the Dialogic SR140 T.38 stack — the same engine embedded in many of the world’s most widely-deployed fax server products. Compatibility isn’t a workaround. It’s foundational.

Enterprise Fax Server Software

T.38 SIP Stacks & Drivers

Dialogic SR140 — The industry-standard FoIP engine. T38Fax is one of only a handful of SIP trunk providers officially certified for SR140.
XCAPI — Virtual FoIP modem with T.38 support.
Fax Voip T38 Fax & Voice
Dialogic Brooktrout FSP

Running a fax server? See our dedicated Enterprise Fax Servers page for the full picture — architecture, ECM error correction, security, and why our SIP trunks outperform voice carriers for fax workloads.

Softswitches

Softswitches & IP-PBXs

T38Fax works with most T.38-capable softswitches and IP-PBXs. Setup guides and design considerations for each platform are in our knowledge base.

Not Listed?

Don’t See Your Device?

If your device supports T.38, it should work with T38Fax. Our interoperability team is constantly testing new hardware and expanding this list.

Three ways to find out:

Start a free trial — 30-day trial with a $25 credit. Connect your device and test it yourself with unlimited support.
Run our ECM self-test — Automated test that checks your T.38 and ECM status in minutes. Free, no account required.
Contact us — Tell us what you’re running. Our team will let you know if it’s compatible and help you get it connected.

Running a fax server? See why T38Fax outperforms voice carriers for RightFax, HylaFAX Enterprise, GFI FaxMaker, and XMedius — the technical case for our in-house T.38 stack and ECM error correction.

Enterprise Fax Servers

Ready to see pricing? One Power-T.38 SIP trunk. No concurrency limits. No per-page fees. No annual contracts.

View Pricing

Frequently Asked Questions

: Check the device specifications for T.38 support — it’s usually listed under fax or codec settings. If it’s listed, it should work with Power-T.38 SIP trunks. You can verify by signing up for a free trial and running our automated ECM self-test to confirm T.38 and ECM are active on your connection.
: You need an ATA that supports the T.38 protocol — not all do. The Grandstream HT80x series, Cisco ATA 191/192 (MPP), and Poly ATA 400/402 are the most popular choices. All three are T38Fax-certified with step-by-step setup guides in our knowledge base.
: Yes. Most standard fax machines work with T38Fax when connected through a T.38-compatible ATA. Plug your fax machine into the ATA’s FXS port, configure the ATA with your Power-T.38 SIP trunk credentials, and you’re faxing over IP. Some Toshiba and Lexmark MFPs support T.38 natively and can connect without an ATA.
: If your device supports T.38, it should work. Our interoperability team is constantly testing new hardware. Contact us with your device model and we’ll let you know, or sign up for a free trial and test it yourself — there’s no risk.