NAISENTENSOHOSHIKI

摘要

PURPOSE:To attain the extension transfer by returning the signal on an up-bus line to a down-bus line in a main transmitter. CONSTITUTION:A follower transmitter 2i transmits an extension transfer start request signal to a main transmitter 1 from an extension transfer signal detection/insertion circuit 13 by means of a specific bit S1 of an auxiliary channel in a frame of an up-but line and via a bus line 5. The transmitter 1 detects the request signal by a signal detection/insertion circuit 10 and then detects the idle state of an information signal channel by means of the corresponding specific bits SB1-SBn. Then the transmitter 1 transmits simultaneously the extension transfer permission signal and the extension transfer channel designation signal to follower transmitters 2i-2n respectively by means by specific bits S1' and SB1'-SBn' of auxiliary channels in a frame of a down-buts line and via a bus line 4 and transmits the extension transfer signal to a channel network 6. At the same time, this tranfer signal is returned to the corresponding specific channel in the frame of the down-bus line.