REMOTE SUPERVISORY AND CONTROL SYSTEM

摘要

PURPOSE:To transmit specific data at a short period through a communication line in a state of transmitting plural data in a prescribed period through the same communication line. CONSTITUTION:In a system connecting a control station 2 to a supervisory and control station 3 through a communication line 4, a specific data collecting means for collecting specific data DS out of plural data D at a short period TS shorter than a normal period T0 at the time of receiving a specific control command CS from the station 3 and a DTMF modulator 23 for modulating the specific data DS collected at the short period TS to a DTMF signal, superposing the DTMF signal to data D being transmitted through the line 4 and transmitting the superposed signal to the station 3 are added to the station 2. A DTMF demodulator 24 for demodulating the DTMF signal received through the line 4 into the original specific data DS is added to the station 3.