| 摘要 |
PURPOSE:To allow a different master equipment side to grasp the communication between a slave equipment and some master equipment by turning the talking circuit of the master equipment not in operation when the other master equipment is used as the master equipment, and flashing the power source pilot lamp of the master equipment when the other master equipment is in use. CONSTITUTION:Terminals X and Y are at an ''L'' in a stand-by state, neither of the outputs of oscillation circuits OSC1 and OSC2 appears at output sides 3 of NOR gates Ic8 and Ic10, and the outputs are invariably at an ''H''. Power source pilot lamps LED1 and LED2, therefore, turn on continuously. When a master station A enters an off-hook state by a call from a slave equipment, an ''H'' signal is inputted to the terminal X, the ''L'' signal of the output side 2 of an inverter Ic1 is inputted to the input terminal 1 of an inverter Ic5 on the side of a master equipment B, and the input terminal 1 of a gate Ic9 is held at the ''H''. The master equipment B is in an on-hook state at this time, and the input terminal 2 of the gate Ic9 is still at the ''H'', so a signal which makes the talking circuit of the master equipment B inactive is outputted to a terminal F and the output of the OSC2 is outputted by the gate Ic10 to flash the power source pilot lamp. When the output of the inverter Ic1 goes down to the ''L'', the LED1 is on continuously on the side A. |
