T38Fax
About
T38Fax is a SIP trunk carrier specializing exclusively in T.38 fax over IP, founded in 2002 by fax industry veterans. The company built its own T.38 stack and places media gateways inside carrier networks to provide reliable fax transmission with Error Correction Mode enabled on every call. T38Fax serves enterprise fax server operators, voice service providers seeking fax offload, and businesses replacing POTS lines with fax-optimized SIP trunks.
Details
VenSearch Intelligence
Ideal Customer
- T38Fax targets a wide range of fax-dependent organizations, explicitly serving three audiences: businesses replacing POTS lines with ATAs or IP-PBXs, enterprise fax server operators running platforms like OpenText RightFax or HylaFAX Enterprise, and voice service providers (ITSPs and UCaaS platforms) seeking to offload fax traffic.
- Regulated industries — healthcare, government, finance — that require reliable, compliant fax transmission at scale are a core sweet spot, as are MSPs and VoIP service providers who resell or white-label the service.
Key Differentiators
- T38Fax's core differentiator is its purpose-built, fax-only network — unlike voice carriers that add T.38 as an afterthought, T38Fax built its entire infrastructure around fax transmission and developed its own proprietary T.38 stack in partnership with Dialogic around the SR140 engine, reportedly achieving the highest interoperability test scores Dialogic had ever recorded.
- ECM (Error Correction Mode) is enabled on every call without exception, which T38Fax argues most carriers disable to reduce processing load — resulting in faxes that appear to succeed while arriving corrupted with neither party aware.
Industries Served
- T38Fax serves regulated and fax-dependent industries including healthcare, government, military, financial services, legal, and education.
- Healthcare is the most prominently featured vertical, with HIPAA-compliant architecture and BAA availability cited as core selling points for hospitals, medical offices, and labs transmitting protected health information.
Service Coverage
- T38Fax provides fax-optimized SIP trunks primarily within the United States and Canada.
- Outbound fax calls are supported to US, Canada, Puerto Rico, US Virgin Islands, and Guam, while inbound DIDs can accept calls from any international caller, though number provisioning is limited to the 48 contiguous US states.
Partnerships
- T38Fax operates a formal Interoperability Program through which hardware and software vendors certify their devices against T38Fax's network and receive published configuration guides and a listing on the partners page.
- Current certified interoperability partners include Cisco, Asterisk, Dialogic, FreePBX, Obihai, Grandstream, Multitech, Mediatrix, AudioCodes, and NetGen.
Company Size & Ownership
- T38Fax Incorporated was founded in 2002 (with the legal entity incorporated December 31, 2001) and is headquartered in Conshohocken, Pennsylvania, just outside Philadelphia.
- The company is small, with approximately 11–13 employees across engineering, technical, sales, finance, and customer support functions according to LinkedIn, Tracxn, and RocketReach.
Compliance & Certifications
- T38Fax holds SOC 2 certification, independently audited by a third-party CPA firm confirming its security controls meet the Trust Services Criteria.
- The company is HIPAA compliant by architecture — fax content traverses the network in real time and is never written to persistent storage — and provides a Business Associate Agreement on request at no additional charge to any customer transmitting protected health information.
Compiled from public sources by VenSearch · Last researched October 14, 2026
Offerings
10 offeringsBusiness Associate Agreement (BAA)
T38Fax provides a Business Associate Agreement on request to any customer transmitting protected health information, with no requirement to be at a specific pricing tier or volume commitment. The BAA documents T38Fax's HIPAA obligations in writing and is available to healthcare organizations that need written confirmation of the company's compliance posture. Supporting HIPAA documentation can also be provided for compliance records.
Direct Cloud Interconnects
Direct network connections for organizations running fax servers or fax-capable infrastructure in cloud environments such as AWS and Azure, allowing them to connect to T38Fax without routing traffic through an on-premises network. Available for environments where standard SIP over the public internet does not meet network policy requirements. Customers must contact the sales team to discuss their specific architecture and connection model.
ECM Test
A free diagnostic tool that tests whether a customer's current T.38 provider has Error Correction Mode enabled, completing in under two minutes with no signup required. ECM is the fax protocol mechanism that detects corrupted pages and requests retransmission, and most T.38 providers disable it. The test helps customers identify whether their current carrier's fax implementation is causing undetected transmission failures.
IPSec VPN Encrypted Transport
Optional IPSec VPN tunnels that encrypt the SIP signaling and UDPTL media path between a customer's network and T38Fax's gateways, so fax traffic travels over an encrypted channel rather than the public internet. Available at no additional charge and is suited for organizations with security or compliance policies requiring encrypted transport. Applicable to HIPAA-regulated environments and other regulated industries.
Power-T.38 for Business Fax Connectivity
Fax-optimized SIP trunks for businesses connecting analog fax machines via ATAs, IP-PBXs, MFPs, and fax servers as a replacement for POTS lines. Supports multiple deployment configurations including ATA direct connect, IP-PBX with ATAs behind it, and direct fax server registration, with certified compatibility for devices including Grandstream HT8xx series, Cisco ATAs, AudioCodes, Patton, and major IP-PBX platforms. Pricing is usage-based with no activation fees, no minimum term, and a 30-day free trial with $25 credit included.
Power-T.38 for Enterprise Fax Servers
SIP trunks engineered specifically for enterprise fax server software including OpenText RightFax, HylaFAX Enterprise, GFI FaxMaker, and XMedius. The service uses T38Fax's own T.38 stack with ECM error correction enabled on every call, and is certified for use with the Dialogic SR140 T.38 stack embedded in major fax server products. Includes full compatibility documentation, setup support, and unlimited technical support from fax industry engineers.
Private Dedicated Circuits
Private SD-WAN or direct circuit connections between a customer's facility and T38Fax's network for environments where security policy prohibits fax traffic from traversing the public internet. Designed for government, financial, and defense-adjacent environments requiring full network isolation. Additional monthly charges apply and customers must contact the sales team for details and lead times.
Reseller & Integration Partnerships
A partner program for resellers and integration partners referenced on the T38Fax website under the Partners section. The program is described as covering reseller and integration partnerships, though detailed terms are not provided on the analyzed pages.
Service Provider T.38 Offload
A wholesale fax offload service for ITSPs, UCaaS providers, and other voice service providers that allows them to route customer fax traffic to T38Fax's network instead of relying on their upstream carrier's inconsistent T.38 implementation. The model involves establishing a SIP trunk interconnect, routing fax DIDs to T38Fax, and letting end customers' equipment interact directly with T38Fax's media gateways, making the offload transparent to end customers. Wholesale volume pricing is available for providers meeting volume commitments.
Unlimited Technical Support
Unlimited technical support included on every plan from the free trial through enterprise, staffed by fax industry engineers who diagnose issues using Wireshark captures, protocol analysis, and T.30 negotiation knowledge rather than scripted troubleshooting. Support covers fax-specific diagnostics including T.38 negotiation failures, ECM handling, ATA misconfiguration, and network path issues. Customers open support cases through a helpdesk system that routes issues to the appropriate queue.
Considering T38Fax?
Our team will work with you to determine if T38Fax is the right fit for your organization. From research and assessment through procurement negotiation and ongoing vendor management — we handle the entire process at no cost to you.