| 摘要 |
PROBLEM TO BE SOLVED: To accurately set the time indicated by the timer circuit of a master telephone set of cordless extension telephone even in the place where public time information is not avaiable by utilizing the signal transmission to a slave telephone set from the master telephone set. SOLUTION: A control circuit 3 in a master telephone set 1 of cordless extension telephone acquires time information through a telephone line at, for example, every 24 hours and corrects the time indicated by a timer circuit 2 in accordance with the acquired time information. When an incoming call arrives at the telephone set 1 or a slave telephone set 5 makes a telephone call to the set 1, the telephone set 1 transmits a sound signal or a signal detecting the telephone set 5 to the telephone set 5 from a transmission circuit 4 together with the time information corresponding to the time indicated by the circuit 2. A reception circuit 9 in a radio wave correcting clock 6 receives the transmitted signals by means of an antenna 9a, only separates the time information from the received signals, and corrects the time displayed on a time displaying section 7 based on the separated time information. |
