METHOD AND APPARATUS FOR ELECTRONIC PAYPHONE OPEN SWITCH INTERVAL MANAGEMENT

Control apparatus for a line operated telephone is described. This control circuitry is designed to be primarily telephone line powered and to not employ a large capacitor for storing power to sustain the circuitry during open switch intervals in which the telephone line is not powered. Rather, the present circuitry includes a telephone line monitoring circuit for sensing a power down condition, a processing means such as a microprocessor with an associated power down program for storing process status at a time just prior to power down and for resetting the processing at the appropriate place upon power up, and low power state monitoring latches for monitoring important events, such as an on hook condition, coin collection and refund operations occurring during an open switch interval. In combination, a low power operation is achieved primarily utilizing a regularly interrupted source, the phone lines, and requiring only a small battery to power the low power monitoring state monitoring latches.