AC Signal-activated switching apparatus

摘要

Apparatus is disclosed for disconnecting and reconnecting equipment to a telephone line in response to at least one AC signal sent over the telephone line. The equipment can automatically be reconnected after a predetermined time period, or reconnected only after another AC signal is received. The apparatus includes digital circuits for detecting a signal within a predetermined frequency range which is present uninterrupted for a minimum time period to activate switching. The apparatus also includes digital timing circuits which can provide relatively long time periods during which the equipment is disconnected which do not utilize large energy storage devices. The digital circuits of the apparatus are operable at extremely low currents, e.g. less than 30 ua total drain. The regulator utilizes one or more light-emitting diodes drawing a current of only about 5 ua to generate a reference voltage.