| 摘要 |
PURPOSE:To save communication processing amount by allowing each line device to process singly normal connection for accommodated lines and apply communication with a controller after the connection with a line accommodated in other line device or other controller in addition to quasi-normal connection such as busy tone processing at busy state of a called party and abnormality processing such as fault processing. CONSTITUTION:When a subscriber A makes a call to a subscriber B accommodated in the same line device LE1, a central controller CC1 reference the own ilde memory 1B and the own subscriber data memory SD, and when the subscriber B is idle and connectable to the subscriber A, connection switch SW1 is controlled and th subscribers A, B are connected. In this case, the central controller CC1 makes no communication to a controller CE. When the subscriber B is busy and not connectable to the subscriber A, the central controller CC1 connects the subscriber A to an optional communication channel CL via a connection switch SW1 and requests busy tone processing to a central controller CC2 of the controller CE via a control channels SL. In the controller CE, the central controller CC2 transmits a busy tone to the communication channel CL connected to the subscriber A via a connection switch SW2. |
