Patent ID: 6301344
Filing Date: 2001-10-09
Classification: H04M

Abstract:
An intelligent public telephone comprising:an operating system including an application specific integrated circuit operable with a microprocessor;a delta-sigma modulator circuit integrated into the application specific integrated circuit for simplifying audio functionality thereby improving product reliability;a high-speed, bi-directional, one-wire master controller integrated into the application specific integrated circuit for facilitating serial communication with a telephone operating device selected from the group consisting of a resident electronic serial number device, custom integrated circuits operable therewith, product option cards, and a multi-functional product interconnect port;a low power, low impedance hookswitch control circuit integrated into the application specific integrated circuit for improving the affects of intruding water that can cause a false hookswitch indication;a programmable coin debounce and detection circuit integrated into the application specific integrated circuit;secured memory page-swapping means for a 64 kbyte direct address system integrated into the application specific integrated circuit;battery diagnostic means operable with a battery of the operating system, the battery diagnostic means communicating with the microprocessor for providing a signal thereto indicative of battery capacity while maintaining the battery transparent to operation of the telephone;pin fraud prevention circuitry communicating with the microprocessor and handset for permitting operation of the public telephone upon an enabling signal therefrom to improve product robustness for minimizing potential fraud; andfirmware security means for providing firmware security and configuration control of the operating system, and for facilitating flexibility in managing the configuration control.