| 摘要 |
PURPOSE:To eliminate useless occupancy of a telephone line, by detecting the start and the end of a call, and lighting a light emitting element during the call so as to discriminate whether or not a handset is hooked correctly on a hook of a telephone set. CONSTITUTION:When an input from an operating section 2 exists, a called telephone number is extracted from a telephone number memory 17 by a central processor 7 via a data bus and outputted to a dial signal converting section 4. Further, a signal is transmitted to an opposite party from the converting section 4 and when a response signal comes from the opposite party, it is detected at a signal detecting section 5 to light up a display lamp. When the call is finished, the detecting section detects it to turn out the display lamp. Then, it is detected easily whether or not the handset is placed correctly on the telephone set, allowing to eliminate useless occupancy of the telephone line. |
