Fax Over IP, Done Right.
The T.38 Carrier Built by Fax Experts
The voice-centric SIP trunking industry treats real-time fax as an unwelcome nuisance, and lacks the expertise to help you fax over IP reliably. We built our entire network around fax, including our own T.38 stack with ECM enabled on every call, supported by engineers who've spent their careers in the fax industry. Who would you trust?
- 30-day free trial
- Unlimited technical support
- 100% satisfaction guarantee
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What Actually Makes the Difference
Most T.38 failures trace back to the same causes. Here's how T38Fax addresses each of them.
Consistent T.38
We built our own T.38 stack and place our gateways inside carrier networks. Your equipment terminates on our gateways on every call — no upstream T.38 handoff, no variable routing, no mystery failures.
Why it mattersECM Always Available
Error Correction Mode is the part of the fax protocol that detects corrupted pages and requests retransmission. Most carriers disable it to reduce load. Without ECM, a fax "succeeds" while arriving unreadable — and neither party knows. We offer ECM on every call, without exception.
Test your current providerSupport That Diagnoses
Our fax industry veterans use deep fax-specific diagnostics to investigate transmission issues. When you open a ticket, you immediately reach someone who can tell a T.38 negotiation failure from a misconfigured ATA — and fix it. Unlimited support is included on every plan, free trial through enterprise.
Visit the knowledge baseSecurity & Compliance
SOC 2 certified. HIPAA compliant. Because T.38 is real-time, fax content passes through our network and terminates — we never store your documents. Optional IPSec VPN tunnels available at no additional charge.
Security & compliance detailsBuilt for Your Deployment
T38Fax serves fax server operators, VoIP service providers, and businesses replacing POTS lines. Each use case is handled differently — here's how.
Enterprise Fax Servers
Running RightFax, XMedius, HylaFAX, or GFI? We provide SIP trunks configured specifically for fax server environments, with full compatibility documentation and setup support.
Fax server trunksVoice Service Providers
Offload your fax traffic to a carrier whose T.38 actually works. We interconnect directly with your platform, handle the PSTN termination, and remove fax reliability as a customer service problem.
Provider offload trunksBusiness Fax Connectivity
Moving away from POTS lines, or fax broke when you switched to VoIP? T38Fax connects fax machines, ATAs, and IP-PBXs to reliable SIP trunks with setup guides for every major device.
Business fax trunksDoes Your T.38 Provider Have ECM Enabled?
ECM — Error Correction Mode — is the mechanism that confirms the image you send is the image your recipient receives. Without it, a fax can arrive with blank lines, garbled text, or missing pages while the confirmation shows "success." Most T.38 providers disable it. Take our free test and find out in under two minutes.
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"We've sent several million faxes since migrating to T38Fax, and we've not had a single demonstrable case where faxes fail when using T38Fax but succeed with our previous carrier."