(under subclass 164) Subject matter wherein plural stations, each having both a transmitter and receiver, are serially linked by the transmitter of the preceding station transmitting to the receiver of the next station and the last station of the system transmits to the receiver of the first station of the system.
(1) Note. If one of the stations or lines develops a fault; the last transmitted signal, which is not received by the next station intended for receipt, will be returned (loop back) to the preceding station so this station knows that the transmitted signal has not been transmitted through the entire system.
