| 摘要 |
PURPOSE:To facilitate information communication betwen the switchboard and the exchange main body, by not only inverting the electric polairty of the down line from the exchange side to the switchboard but also closing the switchboard indenpendently of the will of the oprator and by detecting this polarity conversion to report switchboard closure to the operator. CONSTITUTION:In the electronic exchange system where control information for key information of switchboard 1 and visual information such as lighting of lamps and so on are transmitted and received between exchange main body 2 and swichboard 1 which handles manual and semiautomatic calls according to intervention of the operator, the polarity of up line 3 to main body 2 is inverted by switchboard 1 to report that switchboard 1 can be handled when switchboard 1 can handle calls by electric power supply or depression of the seating information key dependent upon th operator. Further, after detecting polarity change in the main body 2 side, the polarity of down line 4 to switchboard 1 is changed, and polarity change is detected in the switchboard 1 side and is reported to the operator by visual display on switchboard 1 or sound, thus facilitating information communication between switchboard 1 and main body 2. |
