FIELD: communication. SUBSTANCE: digital cellular communication system has two-way communication line with pulse-code modulation to transmit coded speech and controlling data in the form of blocks, commutation unit connected to first end of communication line with PCM and base station connected to second end of communication line with PCM. Commutation unit incorporates speech encoder to code speech signals and generator of code of detection of error in encoded speech signal. Base station includes error detector in communication line with PCM that signals presence of error in received block in response to received block containing error. Base station additionally has unit processing errors in communication line connected to error detector in communication line with PCM to leave out received block in response to signal indicating presence of error in this block and to replace this block with controlling default bit subject to sending to mobile station. As result mobile station does not perform any operations except operation of masking of bad frame in response to reception of controlling default bit. EFFECT: improved quality and reliability of communication. 22 cl, 7 dwg
