| 摘要 |
PURPOSE:To allow a caller to transfer to other house call by displaying a busy state to a person called later when the same house is called duplicatedly in a multi-cahnnel system and extinguishing the house number light as well so as to allow the caller to use an idle communication line. CONSTITUTION:When a master controller discrimiantes the duplicated call as to the same house number, a same house call signal is inputted to a on-shot multivibrator circuit 13, the pulse signal of a prescribed short time is inputted to an OR gate 14 from the circuit 13 and a busy display light 12 is lighted. Thus, the call of the same house, that is, the busy state is discriminated to a person calling the same house with a delay even during the line is idle. In the embodiment, since the display goes off immediately after the busy dislay is finished for a prescribed time by the circuit 13, the call of other house utilizing an idle line is attained immediately to offer convenience. The call house number displayed on a display section 9 also goes off by clearing a latch 10 when the one-shot pulse is lost.
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