voice operated transmission (VOX)

Voice Operated Transmission (VOX) is a voice-controlled transmission. It is used in mobile communications systems such as GSM and in satellite transmission. In this type of transmission, radio transmission is activated only when a voice signal is detected.

If the VOX system does not detect any voice signals, the carrier signal is not transmitted. The advantage is that energy consumption is reduced during voice pauses, which results in a longer battery life. In addition, the radio channel can be made available for other purposes during the transmission pauses.

If the carrier signal is not transmitted, this could irritate the communication partner, who could assume that the transmission is interrupted. For this reason, voice pause detection is used and the transmission channel is assigned Comfort Noise( CN).