DIGITAL SIGNAL BUS REPEATING SYSTEM

PURPOSE:To eliminate the need for a response signal and a response signal line for controlling a repeater by detecting the signal state on a data signal bus and controlling the repeater. CONSTITUTION:A detector 10 when detecting a voltage equivalent to a logical value '1' on one of signal lines constituting the data signal bus 12 controls the repeater 7 into an operation state and sends the output of an input/output circuit 3 to a control circuit 1 through the repeater 7. When the input/output circuit 3 outputs a voltage with a logical value '0' to respective signal lines of the data signal bus 12, a detector 10 detects that and controls the repeater into a nonoperation state, so the data signal bus 6 enters the state of the logical value '0' through a pull-up circuit 8.