| 摘要 |
PURPOSE:To realize an interruption call without giving any confusion to the subscriber to receive an interruption while talking, by sending the interruption warning tone to the subscriber to receive an interruption prior to the interruption. CONSTITUTION:In case the telephone number dialed by the subscriber A is to the subscriber B or C under talking, the busy tone sending trunk BT0 is started from the CPU and via the signal distributor SD to give a display of the busy state to the subscriber A. In this case, if the terminating subscriber permits the interruption, another busy tone BT1 is sent to show the possibility for the interruption call. Thus the subscriber A requests an interruption call, and thus the exchange unit sets up the channels at the interruption call trunks CFT for the subscribers A, B and C each. And at the same time, the interruption warning tone TNT1 is sent to the CFT. In such way, the interruption warning tone can be sent to the subscribers A, B or C, and an interruption call is carried out after a fixed time. |
