Importance

Loading Importance Indicators...

Abstract

A master station 1 is connected with a telephone line 2. For this master station 1, a plurality of hand sets are provided. Each hand set is set to different transmitting and receiving frequencies to communicate with the master station 1. Each hand set generates from an information signal generating circuit 35, an information signal representing the operation state of the hand set and transmits the information signal by a transmitting circuit 37. The master station 1 receives the information signal through a monitor receiving circuit 4. The monitor receiving circuit 4 has a receiving frequency which changes cyclically to be tuned successively to all the transmitting frequencies of the respective hand sets. Accordingly, the monitor receiving circuit 4 receives successively the information signals from the respective hand sets. The received information signals are detected by a second detecting circuit 10 and a third detecting circuit 11 to be supplied to a control circuit 3. The control circuit 3 stores the information signals in a status table of a RAM 18. Consequently, by referring to this status table, the operation states of the respective hand sets can be determined.

Loading the Abstract Image...

First Claim