Voice Over IP

PREVALENT MODEMS

The ITU-T is the prevalent standards organization for the publication of modem specifications. Indeed, I doubt a commercial modem can be purchased which does not adhere to ITU-T specifications. These modems are published under the ITU-T V Series recommendations.^[1]

^[1] For more information on V Series recommendations see V Series Recommendations by Uyless Black, The V Series Recommendations: Standards for Data Communications over the Telephone Network, 2nd Edition, McGraw Hill, 1995.

The architecture for the recent V Series modems is based on the V.34 specifications. More recent variations of V.34 are published in V.90 (more commonly known as the 56 kbit/s modem). A later section in this chapter describes the architectures of ...