| 摘要 |
PURPOSE: To prevent transmission of an unnecessary radio wave by confirming contents of the display device of a terminal station or confirming a dial tone at the time of originating. CONSTITUTION: A line control and radio equipment 2 of a host station continuously transmits the transmission signal of a channel 1 and sends an idle line signal 8 indicating whether two channels are idle or not. The terminal station receives and monitors them. The channel 2 is used only at the time of call incoming from a repeating exchange 1 or reception of call originating signals from terminal stations 3 to 5 in the host station. Each terminal station control part 13 always monitors the signal 8; and when there are two idle channels, it is discriminated that broadcasting speech is possible, and this state is displayed on a display device 14. Besides this display, the dial tone showing that broadcasting speech is possible is emitted from a receiver speaker at the time of hooking off the receiver of a telephone set 7. If the signal 8 is not sent or there are not two idle channels, broadcasting speech is inhibited, and the dial tone showing that broadcasting speech is impossible is emitted at the time of hooking off the receiver of the telephone set 7. |
