Intelligent public telephone system and method

• US 6,301,344 B1
• Filed: 11/04/1998
• Issued: 10/09/2001
• Est. Priority Date: 11/05/1997
• Status: Expired due to Fees

• Current Assignee: Protel Incorporated (Inductotherm Group)
• Original Assignee: Protel Incorporated (Inductotherm Group)
• Inventors: Meyer, Rolf, Stirk, Gary L., McBride, Tony L., Felch, Raymond F., Bryan, Kenneth L., Hayes, Stephen J.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): TRAN, QUOC DUC
• Application Number:
  US09/186,009
• Time in Patent Office: 1,070 Days
• Field of Search: 379/143, 379/144, 379/145, 379/146, 379/147, 379/148, 379/149, 379/150, 379/153, 379/154, 379/155
• US Class Current: 379/145
• CPC Class Codes: H04M 1/18 Telephone sets specially adapted for use in ships, mines, or other places exposed to adverse environment H04M1/19 takes precedence
• CPC Class Codes: H04M 17/02 Coin-freed or check-freed systems , e.g. mobile- or card-operated phones, public telephones or booths
• CPC Class Codes: H04M 17/023 Circuit arrangements
• CPC Class Codes: H04M 17/026 Constructional features

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.

Claims

1. 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; and

firmware security means for providing firmware security and configuration control of the operating system, and for facilitating flexibility in managing the configuration control.

2. The telephone as recited in claim 1, wherein the firmware security means comprises storing means for storing a configuration code, a product code, and a revision level indicator in the operating system, wherein recognition of the configuration and product codes permits use of firmware with the operating system when a revision level number of the firmware favorably compares with the revision level of the operating system, and the configuration and product codes carried by the firmware favorably compare with the configuration and product codes of the operating system.

3. The telephone as recited in claim 1, further comprising:

a programmable data storage device for modifying the operating system, the storage device having a configuration code carried therein, wherein the data storage device communicates with the operating system of the pay telephone via an input port for upgrading and revising a telephone control operation only when the configuration code recognizable by the firmware security means for permitting revisions to the operating system configuration provides a favorable comparison between the configuration code of the storage device and a configuration code of the operating system.

4. The telephone as recited in claim 1, wherein the operating system comprises a motherboard and an electronic product code stored within the motherboard.

5. The telephone as recited in claim 1, wherein the battery diagnostic means comprises:

voltage detection circuit for measuring a voltage level of the battery when operating with a known load thereacross, the voltage detection circuit providing a level detection signal to the microprocessor; and

battery charging circuit operable with the battery for charging thereof, the charging of the battery initiated by the microprocessor communicating with the battery charging circuit in response to the level detection signal.

6. The telephone as recited in claim 5, wherein the microprocessor provides a battery charging time period based on the level detection signal, and wherein the operating system provides an output signal indicative of a low battery status.

7. The telephone as recited in claim 5, wherein the microprocessor provides a battery voltage level based on the level detection signal, and wherein the operating system provides an output signal indicative of a low battery status.

8. The telephone as recited in claim 1, wherein the pin fraud prevention circuitry comprises current limiting means for limiting an amount of current flowing through the handset and for providing sufficient operating current while preventing detection by a central office communicating with the public telephone.

9. The telephone as recited in claim 8, wherein the current limiting means comprise:

first current limiting means operable with a positive voltage signal from the handset;

second current limiting means operable with a negative voltage signal from the handset; and

signaling means responsive to the positive and negative voltage signals for providing an handset condition signal to the microprocessor indicative of a handset operable condition.

10. The telephone as recited in claim 1, wherein the one-wire master controller comprises:

a serial interface circuit;

a single wire serial bus operable between the serial interface circuit and the application specific integrated circuit;

processing control software operable with the microprocessor for providing signal timing and protocol for controlling operation of the application specific integrated circuit with the telephone operating device.

11. The telephone according to claim 1, wherein the hookswitch control circuit comprises:

a low impedance input circuit connected to contacts of the hookswitch and the application specific integrated circuit; and

a single flip flop and output buffer circuit integrated into the application specific integrated circuit, the flip flop and output buffer circuit operable with the low impedance input circuit for detecting an off-hook condition and an on-hook condition.

12. An intelligent public telephone comprising:

an operating system including an application specific integrated circuit operable with a microprocessor;

a master controller integrated into the application specific integrated circuit and communicating with a telephone operating device through a single wire connection for facilitating serial communication with a telephone operating device selected from the group consisting of an electronic serial number device and custom integrated circuits operable therewith;

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;

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;

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; and

firmware security means for providing firmware security and configuration control of the operating system, and for facilitating flexibility in managing the configuration control.

13. The telephone as recited in claim 12, wherein the firmware security means comprises storing means for storing a configuration code, a product code, and a revision level indicator in the operating system, wherein recognition of the configuration and product codes permits use of firmware with the operating system when a revision level number of the firmware favorably compares with the revision level of the operating system, and the configuration and product codes carried by the firmware favorably compare with the configuration and product codes of the operating system.

14. The telephone as recited in claim 12, further comprising:

a programmable data storage device for modifying the operating system, the storage device having a configuration code carried therein, wherein the data storage device communicates with the operating system of the pay telephone via an input port for upgrading and revising a telephone control operation only when the configuration code recognizable by the firmware security means for permitting revisions to the operating system configuration provides a favorable comparison between the configuration code of the storage device and a configuration code of the operating system.

15. The telephone as recited in claim 12, wherein the operating system comprises a motherboard and an electronic product code stored within the motherboard.

16. The telephone as recited in claim 12, wherein the battery diagnostic means comprises:

voltage detection circuit for measuring a voltage level of the battery when operating with a known load thereacross, the voltage detection circuit providing a level detection signal to the microprocessor; and

battery charging circuit operable with the battery for charging thereof, the charging of the battery initiated by the microprocessor communicating with the battery charging circuit in response to the level detection signal.

17. The telephone as recited in claim 16, wherein the microprocessor provides a battery charging time period based on the level detection signal, and wherein the operating system provides an output signal indicative of a low battery status.

18. The telephone as recited in claim 16, wherein the microprocessor provides a battery voltage level based on the level detection signal, and wherein the operating system provides an output signal indicative of a low battery status.

19. The telephone as recited in claim 12, wherein the pin fraud prevention circuitry comprises current limiting means for limiting an amount of current flowing through the handset and for providing sufficient operating current while preventing detection by a central office communicating with the public telephone.

20. The telephone as recited in claim 19, wherein the current limiting means comprise:

first current limiting means operable with a positive voltage signal from the handset;

second current limiting means operable with a negative voltage signal from the handset; and

signaling means responsive to the positive and negative voltage signals for providing an handset condition signal to the microprocessor indicative of a handset operable condition.

21. The telephone as recited in claim 12, wherein the one-wire master controller comprises:

a serial interface circuit;

a single wire serial bus operable between the serial interface circuit and the application specific integrated circuit;

processing control software operable with the microprocessor for providing signal timing and protocol for controlling operation of the application specific integrated circuit with the telephone operating device.

22. The telephone according to claim 12, wherein the hookswitch control circuit comprises:

a low impedance input circuit connected to contacts of the hookswitch and the application specific integrated circuit; and

a single flip flop and output buffer circuit integrated into the application specific integrated circuit, the flip flop and output buffer circuit operable with the low impedance input circuit for detecting an off-hook condition and an on-hook condition.