| 摘要 |
PURPOSE:To decrease the busy state frequencies to a trunk line by connecting automatically an incoming trunk line to a key extension in case an attendant board is kept busy for a prescribed period of time or longer in a trunk line incoming mode. CONSTITUTION:A central controller 7 informs the incoming information on a central office trunk 4 to an attendant board 1 via a switching network 3 and a subscriber circuit 2 for attendant board. In case the board 1 is busy and unable to give an answer, the busy information is sent to the controller 7 from an attendant board controller 9. Based on this busy information, the controller 7 starts a busy time counter 10 and at the same time obtains the information periodically from the controller 9. In case the board 1 is still kept busy despite a counting action for a fixed time set previously, a trunk line incoming call is connected to a key extension 11 and then to the trunk 4 via a subscriber circuit 12 and the network 3. |
