V.34 Fax Modem

Commetrex’ V.34 Fax Modem implements the ITU-T V.34 recommendation for a half-duplex analog modem operating at data signaling rates of up to 33,600 bps. The product implements the basic and optional baud rates of 2400, 2743, 2800, 3000, 3200, and 4429 symbols per second, providing data rates of 2400 to 33,600 bps in increments of 2400 bps.

V.34 is able to support high-density constellations, such as the one to below, due to its ability to adapt to the channel. In lower-speed modems, such as V.17, the data are exchanged assuming a nominal bandwidth with a fixed carrier. However, in V.34, both the signaling and carrier frequencies are adapted to the call’s channel as determined by the receiver’s probing-tone analysis.

The product package includes the V.8 modem that includes the V.21 full-duplex modem and the V.8 session-control procedures. Related products include Call Progress Analysis with ANSam detection), a Call Classifier with fax calling-tone (CNG) detection, and the MSP PCM Interface Boards. Of course, all of this is available as part of the comprehensive Open Telecommunications Framework® telephony platform for system developers or as a separately licensed media technology.


  • V.34 compliant
  • Fully compatible with Group 3 fax
  • Texas Instruments XDAIS compliant
  • OpenMedia™ compliant
  • Support for the Texas Instruments ‘C6400 DSP
  • Portable ANSI C version
  • Mu-Law & A-Law support
  • Designed for multi-channel operation


  • Cuts fax-call times in half
  • Reduced development time and cost
  • High customer satisfaction
  • Deployment flexibility