The Sansay MST is a transcoding subsystem that enables communications service providers to convert the media encoding of audio, fax, and video traffic. The MST enables operators to support an increased variety of devices and codecs, reduce carrier termination costs, and enhance security through traffic encryption. The MST functions as a transcoding resource within Sansay’s VSXi session controller. The VSXi uses H.248 to direct media streams to the MST as a part of normal session control functions and traffic handling. By deploying the MST as a part of VSXi session control, transcoding is performed with the same active level of session control, reporting, and high availability as standard VSXi media handling.


The VSXi cost-effectively supports a distributed deployment, enabling service providers to extend security functions and optimize session routing. Transcoding as a part of distributed deployment offers two clear benefits for service providers:

  • Eliminates added signaling, CDRs, and session ports required by outboard transcoding
  • Transcodes with minimal network hops and minimizes possible traffic hair-pinning

Transcoding as a part of session control functions results in simplification of network operations as well as optimized session routing which can result in reduced latency and jitter.

MST setup and configuration is performed through added elements in the VSXi GUI. Sessions are targeted for transcoding by trunk ID (TID). Codecs are specified using a drop-down selection.

The MST is a straightforward addition for VSXi operators looking to add transcoding.

MST Datasheet