OUT-OF CALLING RANGE INFORMING CIRCUIT FOR CORDLESS TELEPHONE SYSTEM

摘要

PURPOSE:To prevent a cordless telephone set from sending a noise to a telephone line when it moves outside of a calling range and to send an out-of range movement information sound to the cordless telephone set and the telephone line. CONSTITUTION:In a connecting device 1, a field intensity detection part 106 constantly monitors the field intensity of the radiation radio wave of the cordless telephone set 2. Then, when electric intensity becomes less than a set level, switch S1 181 is opened to release a calling route and switches S2 182 and S3 183 are closed to connect a sound source 102 to a calling route on the side of a line wire 3 and a calling route on the side of a transmission part 104 so as to send the outside of the circle informing sound to the line wire 3 and the cordless telephone set 2. Thus, even when the cordless telephone set moves outside of the calling range, an uncomfortable noise is not sent to the telephone line and that the cordless telephone moves outside of the range is informed to both of the telephone line and the cordless telephone set so that a telephone subscriber who is calling can recognize that a calling disconnection is not caused by a fault and a cordless telephone set user can quickly return to the calling circle.