| 摘要 |
PURPOSE:To form a broadcast equipment between a supervisor room and each housing by setting an interphone between each housing and a supervisor room to exclusive use of reception at each housing and to exclusive use of transmission at the supervisor room in a collective dwelling house. CONSTITUTION:A talking line 2 and a transmission line 3 are connected to a central controller 1 installed at a supervisor room, and interphones 4-1-4n of each housing are connected to the talking line 2 and the transmission line 3 in the multi-drop system. The controller 2 changes over a selection switch to the broadcast mode to select a housing to be broadcast. When an address data succeeding to a start signal from the transmissionn line 3 and a transmission/ reception circuit 48 is coincident with the address of own station in a housing interphone 4 and the succeeding control data is a data representing the broadcast, a line connection relay 49 and an electronic switch 47c are closed, an amplifier 43 and a speaker 44 are connected to the talking line 2, and loudspeaker reception control is applied. A talking circuit 45 and a handset 46 are disconnected from the talking line 2 in this case to inhibit mutual communication. Thus, the broadcast line is formed from the controller 1 via the talking line 2 and the speaker 44. |
