To accurately transmit the information of continuous signals and the information of non-continuous signals through one signal line by detecting the both-terminal voltage of a reference resistor for respective prescribed currents made to flow in a positive direction or a negative direction between a pair of input terminals.
Constant current circuits 46a and 46b are serially connected between a pair of the input terminals 31a and 31b. Respective diodes 48a and 48b as rectifier elements are connected between the sources and drains of MOS type FETs 36a and 36b inside the respective constant current circuits 46a and 46b by polarity shown in the figure. Thus, no matter which polarity of a positive pole side and a negative pole side the continuous signals and the non-continuous signals inputted to the input terminals 31a and 31b are provided with, a current is surely made to flow to the respective reference resistors 34a and 34b though a flowing direction is different. Thus, since the information of the continuous signals and the information of the non-continuous signals are accurately transmitted through one signal line, the reliability of a system incorporating this device is improved and constitution is simplified.
ABE RYOSUKE
TADANO HIROYUKI
MAEDA YOICHI
YAMANO SEIICHI
TSUCHIYA MASARU
NIPPON TELEGRAPH & TELEPHONE
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