| 摘要 |
<p>A hierarchical bus type multidirectional multiplex communication system has a relay station (R) and two tributary stations (T1 : T2). A downward transmission line (D) and an upward transmission line (U) are provided between them with a control channel (CCH) and n voice channels (VCH1-VCHn) respectively. Control channel use flag data (101) showing a "free" or "engaged" state of the channel, mode data (102) showing "a control channel retention mode" or "a call-out mode", call-out station number data (103) showing "a station number of a call-out tributary station", transmission voice channel number data (104) showing "a voice channel number for transmission", reception voice channel number data (105) showing "a voice channel member for reception", and call-in subscriber number data 106 showing "a subscriber number of a call-in subscriber", are multiplexed on the control channel CCH. Voice channel use flag data (201) showing a "free" or "engaged" state of the channel and voice data (202) are multiplexed on the voice channels (VCH1-VCHn). Upon failure of the relay station, a return circuit (6) returns signals from the upward line (4) back onto the downward line (D). The function of the relay station can be taken over by the tributary stations without complex control of station data in the relay station. <IMAGE></p> |
