| 摘要 |
PURPOSE:To confirm the presence of a dial and to eliminate the need for other lighting devices even with dialing at a dark place, by the constitution that a lighting device is illuminated when a call tone rings for a telephone set or dialing is done. CONSTITUTION:S1 and S2 are interlocked with a hook switch of a telephone set, and when a handset is hooked up, the S1, S2 are closed, a lighting device PL1 such as a lamp or a light emitting diode is illuminated with a battery E to directly or indirectly illuminates the surface of a dial. When a called party hooks up its handset, a relay RV is activated through the inversion of L1 and L2 and the PL1 is distinguished through the open contact RV1. When a call bell of the telephone set rings, since a callout signal current in 16Hz flows to the L1 and L2, a lighting device PL2 is illuminated to inform the location of the telephone set. |
