Refund system for coin:operated telephones - uses low power CMOS circuits calculating credit and initiating refund relay, powered from capacitor during power failure (NL 19.12.77)

摘要

The refund system for coin-operated telephones without stand-by power supplies, enables a refund to be given for unexpired time even in the event of power failure. The central unit of the subscriber apparatus (1) for calculating the remaining credit, is constructed from a microprocessor. The data is transferred to a register (3) using circuits with very low power consumption, e.g. C-MOS type electronic units. The outputs from these circuits operates the coin-storage and refund mechanisms via relays (5-7). The mains-fed power supply unit (2) is connected to the register via a signal line (m) and a diode-capacitor energy-storage device (4). In the event of a mains failure, sufficient power is thus made available to operate the coin-refund mechanism and to hold the payment due to the authorities in an intermediate store until the mains power is restored.