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Fax and Modem over IP

Mediatrix_fax_over-ipFor many enterprises in different industries, fax and modem transmissions remain one of the most important communication methods. In areas such as finance, government, law, health, real estate, offshore, etc., fax and modem over IP are one of the essential ways to transfer a large number of documents and data, on a daily basis.

Keeping the reliability and quality of those communications without risk while migrating from TDM-based PBXs to IP telephony networks can be a challenge. During the transition from traditional telephony lines to VoIP in the operator network, or the existing legacy telephony systems to the IP-PBX and IP-phones inside enterprises, some interoperability issues may occur between different fax protocols and standards used by the VoIP systems and the enterprise.

Media5 Expertise – What We Offer


Media5 VoIP Adaptors (ATAs), Media Gateways and Session Border Controllers (SBCs) overcome IP fax and modem interoperability challenge by normalising the transmission across the networks, ensuring great flexibility, cost savings and high quality of service.


When it comes to faxes and modems, reliability and security are pre-requirements for many businesses that cannot suffer from failure or loosing data. Media5 solutions offer trustful connectivity and communications to the new IP telephony infrastructure in many scenarios and are adaptable to specific enterprise needs.


Key Benefits

  • Highly interoperable with hundreds of faxes and modem models.
  • Zero touch configuration and easy installation.
  • Portfolio with several ATAs, Media Gateways and SBC models to address operators’ needs of deployment.
  • Compatibility with all SIP protocols and all codecs for fax and modem, such as G.711 and T.38.
  • Survivability: No risk of failure and poor communication during the PSTN replacement.
  • Flexibility to deploy the equipment at the service provider or enterprise, on the edge or in the network, according to the requirements.
  • QoS control for data transmission quality.
  • Cost savings made possible when keeping the existing legacy investments.



A Partner for Reliable Deployments


Due to the high interoperability and quality of Media5 products, the major telecom operators doing PSTN replacement in the world choose Media5 for their deployments:

  • SIP Trunking: Media5 gateways connect to legacy PBX (PRI/BRI);
  • IP Centrex: Media5 ATAs connect multiple analog ports to phones, faxes, and modems;
  • PSTN Replacement.

Regardless of the use case or scenario, Media5 has the best solutions with VoIP adaptors, media gateways, and SBCs to keep the communication through faxes and modems reliable and cost effective for operators and enterprises.


Fax and Modem over IP – Quality Assurance


For each new firmware release, Media5 technologies go through a complete Quality Assurance Test Plan ensuring improved quality to the launch:

  • Software Stability tests
  • Behavior – We make sure that the user experience does not change
  • Features set – We make sure that all fax and modem features perform at their best
  • Audio quality
  • Image quality
  • Modem Connection Reliability
  • Regression tests – We make sure that new releases behave the same way, and better, than older ones

In-House Lab

Media5 has a complete in-house lab where all the tests are made reproducing real life scenarios based on the most complex deployments and, more than this, going further and beyond customers real use cases.

This way we guarantee the durability and resilience of our products to offer the highest quality of service regardless of how Media5 units are used.


Our stringent test procedures for Faxes and Modems include:

  • SIP over TLS, TCP and UDP
  • Secure audio: SRTP
  • Non-secure audio: RTP
  • FAX over PCMA, PCMU, and T.38
  • Modem over PCMA and PCMU
  • Speed tests range from 7200 BPS up to 57.600 BPS

Access to learn more about our complete product set for connecting fax and modem over IP.

Relevant Facts


  • Fax and modem tests take more than 600 hours per each release and minimum of 10 pages per each fax sent/received.
  • Interoperability tests are performed with any fax devices against detailed profiles of 147 V.17 and 27 V.34 fax machines and modems.
  • Release criteria are 99% of success: no image errors are allowed in fax transmissions.
  • More than 3000 fax/modem calls for each release.
  • Less than 10 failures in 3000 calls: less than 0.3%.


Decades of Experience


media5_corporation_logoMedia5 has a long history of technical innovation. Our expertise in analog and digital audio processing started in 1992 as a sound card manufacturer. This in-depth experience with voice digitalization, tone analyzing and firmware development was the definite basis for Media5 to get into the VoIP market in the mid-90s.

Media5 has cumulated 20 years of experience since it entered the IP Telephony industry. The company became one of the pioneers in SIP protocol development standards and has consequently been improving fax and modem transmissions throughout decades.


  • Formally certified in 50 countries with deployments in more than 75 countries
  • Carrier grade quality software and hardware with very low RMA level – below 1%
  • In-house software development, Media5 owns full IPR on its core software
  • Expertise with legacy equipment