| 摘要 |
PURPOSE:To control extension communication and, at the same time, to reduce the personnel expenses and testing time when extension communication is performed between terminals by returning signals of communication channels transmitted from the terminals by means of an additional device without sending the signals to a network terminating device side. CONSTITUTION:When extension communication is made between terminals (TE1 and TE2) in the same house, signals of control channels D and communication channels B1 and B2 are not transmitted to a network side, but returned by means of an additional device (ADP) 20 provided between the terminals and a network terminating device (NT1) 10. The call originating terminal TE1 and call incoming terminal TE2 are connected to a passive bus 25 provided with the communication channels B1 and B2 and an incoming and outgoing control channels D. The additional device 20 for extension communication described in this example is provided on the passive bus 25 between the network terminating device 10 and terminals TE1-TEn. |
