Intelligent public telephone system and method

Abstract

An intelligent pay telephone provides local/remote diagnostics, fraudulent call prevention, capability of facilitating local coin overtime operation, complete cash box accounting, and call detail reporting. Information regarding each call placed from the telephone is recorded and is useful in verifying operator service provider communications, long distance bills, local measured usage charges, and call volume discounts, by way of example. The intelligent pay telephone includes a delta-sigma voice driver for reducing circuit complexity and improving circuit reliability, and a one-wire, high speed communication controller facilitates high speed downloading and uploading of pay telephone data, records, and operating program code. The pay telephone also includes a low impedance, low power hookswitch for resisting damage from weather, as well as a pin fraud prevention circuit for deterring fraud. Battery management techniques, memory management, and coin detection circuits add to the pay telephone intelligence and serve to improve system reliability. And, firmware security techniques and operating system formats promote product firmware security and configuration control.