| 摘要 |
PURPOSE:To prevent a ring-off signal from being sounded from a speaker by placing a subordinate station in a ring-off state by intercepting a transmission output automatically for a certain time before the ring-off signal is sent to a master station, by obtaining the conditions of the ringing-off the subordinate station by ANDing the interception of a received ratio wave and the detection of the ring-off signal. CONSTITUTION:When call buttons 6-1-6-n for kinds of calls are pushed, SELCAL (selective calling system) control circuit 1 applies transmission start signal 10 to transmitter 4 and, at the same time, applies call kind signals 6'-1-6'-n, which correspond to call buttons 6-1-6-n to SELCAL generating circuit 2. This circuit 2 generates and transmits SELCAL frequency signals 7, which correspond to call kind signals 6'-1-6'-n, from transmitter 4 to an antenna to connect the speaker circuit of a selectively called subordinate station. With ring-off button 8 pushed, said control circuit 1 applies start signal 11 to timer 3 and, at the same time, intercepts the output of transmitter 4 to disconnect the speaker circuit of the subordinate station. |
