| 摘要 |
PURPOSE:To reduce ineffective busy time, by providing a busy tone detecting circuit to a network controller connecting such as a storage exchange for facsimile signal and a line exchange so as to inform the detected busy state to the exchange. CONSTITUTION:A facsimile storage exchange 2 is connected to a network controller 4C', which is connected to the line exchange from a line 8 to control a call to a receiving terminal. The network controller is connected to an interface circuit 41-1 via a signal line 7 to make a call to the line exchange from the line 8, and when the receiving terminal is idle, a facsimile data stored in the facsimile storage exchange 2 is transmitted to the receiving terminal. If the calling receiving terminal is busy, a busy tone is returned from the line exchange to the network controller 4C', and when the result is detected at a busy tone detecting circuit 42, it is informed to the exchange 2 via a signal line 7 and the exchange 2 stops immediately the calling. |
