| 摘要 |
PURPOSE:To recognize the arrival of a phone call to its own telephone set by providing a radio call transmitter attached to a private branch exchange and providing plural radio call receivers ancillary to each telephone set so as to allow the user to have only to carry a radio call receiver ancillary on a telephone set. CONSTITUTION:The private branch exchange system consists of plural fixed telephone sets 1a-1m, a private branch exchange 2 connected to lines of the telephone sets, a radio call transmitter 3 ancillary to the private branch exchange 2, and radio call receivers 4a-4n plural number of which are ancillary to each of the telephone sets 1a-1m. Each radio call receiver 4 is provided with a connector 8 able to be connected to a connector 6 of any telephone set 1 and a receiver 10 which has a common extension number to a telephone set subordinated by the receiver 4 among the telephone sets 1a-1m, receives a call signal including its own extension number sent from the radio call trans mitter 3 and informs a carrier of the arrival of a call. |
