MONITOR AND CONTROL SYSTEM USING TELEPHONE CIRCUIT

摘要

PURPOSE:To attain the effective application of a telephone circuit by using a single telephone circuit to set with switching both a unidirectional system and a bidirectional system. CONSTITUTION:A switch 27 changes the reception modes and is set at the time of no person is resident in a room of a transmitter 2 to set an unmanned reception mode. While the switch 27 is reset to set a manned reception mode at the time of an operator is resident. The operator at the side of the transmitter 2 resets the external switch 27 when entering the room. Then the transmitter 2 reads the state of the switch 27 to store it in a memory and then transmits it to a receiver 1. Thus the receiver 1 stores the received switch state information in a memory. As a result, the transmitter 2 has no incoming function any more. Then the switch 27 is set when the operator leaves the room and the receiver 1 rewrites this new state of the switch 27 to the memory. Thus a telephone 26 set at the side of the transmitter 2 has no incoming function nay more.