NOISE ABSORBING CIRCUIT

PROBLEM TO BE SOLVED: To continue the operation of a SCSI system without being affected by noise even at the time of the hot-line insertion and extraction of SCSI equipment by making the input hysteresis width of a signal line larger than the input hysteresis width of an SCSI bus. SOLUTION: A unidirectional noise absorbing circuit 10 consists of a hysteresis comparator 100 and a Schmitt buffer 101 with an enable signal. The comparator 100 is a hysteresis comparator which has hysteresis larger than the specific input hysteresis width of the SCSI bus; and inputs Ein from respective signal lines are led to an uninverted input terminal (+) through a resistance R1 and a reference voltage Es is led to an inverted input terminal (-). Its output is led to the input side of the Schmitt buffer 101. The Schmitt buffer 101 inputs a control signal as the enable signal, and consequently the signal lines are made to conductive/nonconductive.