Telemetry apparatus

摘要

The object of the present invention is to provide the telemetering apparatus, which telemeters electric power, gas, and waterworks, for telemetering via a telephone network with an exchange, wherein the telemetering apparatus responds to the normal polarity inversion, the slow polarity inversion, and calling bell signal applied to the communication line therebetween upon starting or releasing of use of the communication line. To attain the above object, the telemetering appears according to the present invention comprises detection means for detecting a rising edge or falling edge of those polarity inversions and signal characterized thereby with reference to the respective predetermined voltage and the respective predetermined period, thus distinguishing one of these polarity inversions and signal from the others.