| 摘要 |
PURPOSE:To foresee at another slave station that a master station and a specific slave station is in the busy state, by transmitting a signal indicating the busy state from the master station to other slave stations and receiving and displaying this signal in other slave stations when the state between the specific slave station and the master station is busy. CONSTITUTION:When a master station 30 calls a slave station 40-1 a service selecting switch SWt'1 is connected to the side of a messenger call signal generator 33, and a call button P is depressed to be brought into contact with a call oscillator 333, and the call signal from the oscillator 333 is sent to the slave station 40-1 through an LPF331 and an interface IF31-1. Simultaneously, a busy signal generator 341 is driven by the control of a controlling part 35, and a busy signal is sent to slave stations 40-2-40-N through switches SWt'2-SWt'n at a time during the busy state. In the slave station 40-1, the call signal is detected through an IF42-1 and an LPF43-1 by a call detector 45 to light a call lamp L1. An operator confirms lighting of the lamp L1 and switches a switch SWS to the side of a telephone set 44-1. In slave stations 40-2-40-N, the busy signal is detected by busy signal detectors 46-2-46-N to light busy lamps L2, and the busy state of the master station is discriminated. |
