Abstract: A unidirectional bus data communication system which eliminates uncertainty as to the integrity of data received by a receiver connected to the bus, which data may have been involved in truncating collisions. A plurality of data stations are connected to a unidirectional bus which has segments connected to and between the stations. Each of the stations is connected to an upstream segment by a sense (S) lead and to a downstream segment by a transmit (T) lead. Each station is adapted to sense energy via its S lead arriving on an associated upstream segment of the bus and includes a transmitter for transmitting data signals via its T lead on an associated downstream segment of the bus. Signal delay elements interconnect upstream and downstream segments of the bus bypassing each of the stations. The time delay D of each of the signal delay elements is a function of the total interval of a predetermined group of data signal bit durations of the data signals added to a period T.sub.

Abstract: An apparatus and method of communicating data signals on a bus having an upstream portion to which transmitters of a plurality of station are connected, and a downstream portion to which receivers of the stations are connected, and to which an end station is connected having a transmitter connected more upstream than any of the plurality of stations. Signals to be transmitted from each of the plurality of stations are appended to the end of the data stream passing thereby. A bus clear signal is transmitted from the end station, along the bus. When any signal including the bus clear signal is detected from upstream at any of the plurality of stations that might be transmitting, transmission of signals from the plurality of stations is immediately terminated. Transmission of the bus clear signal from upstream thus clears the bus to allow for transmission of different priority signals on the bus.