Communication term, voice service channel is Traffic channel One of. Traffic channel (TCH) carries coded voice or user data. It can be divided into full rate traffic channel (TCH/F) and half rate traffic channel (TCH/H), which respectively carry information with a total rate of 22.8 and 11.4 kbit/s. A half rate channel can be obtained by using half of the time slot used for the full rate channel. Therefore, one carrier frequency can provide 8 full rate or 16 half rate traffic channels (or a combination of both) and include their own path control channels.
The service channels carrying coded voice are divided into full rate voice service channel (TCH/FS) and half rate voice service channel (TCH/HS), with the total rates of 22.8 and 11.4 kbit/s respectively. For full rate voice coding, the voice frame is 20 ms long, each frame contains 260 bits, and the net rate provided is 13 kbit/s.
