System for controlling equipment within a telephone subscriber's premises using DTMF telephone tones

• US 5,548,635 A
• Filed: 01/21/1994
• Issued: 08/20/1996
• Est. Priority Date: 01/21/1994
• Status: Expired due to Fees

• Current Assignee: Sasktel
• Original Assignee: Sasktel
• Inventors: Stretton, Alton O., Bradley, Graham C.
• Primary Examiner(s): Chan, Wing F.
• Application Number:
  US08/184,833
• Time in Patent Office: 942 Days
• Field of Search: 379/37, 379/45, 379/102-105, 348/1, 348/3, 348/6
• US Class Current: 379/102.03
• CPC Class Codes: H04M 11/002 with telemetering systems telemetering in general G08C

Abstract

A system for controlling telephone and non-telephone equipment located on the premises of a telephone subscriber is disclosed. The system includes at least one internal tone control device (ITCD), connected between a telephone outlet and the controlled equipment. The ITCD receives, decodes and validates a sequence of DTMF signals, converts it into a d.c. control signal and monitors the respective equipment with the d.c. control signal which remotely switches on/off the respective equipment. A plurality of different appliances can be operated in a "non-line of sight" mode over the telephone lines. A unique sequence of DTMF signals is associated with each ITCD. The sequence is selected such that the conventional telephone switching center is not activated by it, for avoiding interference between the system of the present invention and the conventional telephone communication. When the equipment is a TV appliance, the system may include a receiving-switching unit connected to the TV cable network and to an optical fiber TV cable, for switching the TV appliance between the two TV networks. In this case, the ITCD is connected to the telephone line and to the receiving-switching unit.

Claims

1. A system for controlling a plurality of appliances at a station which is connected to a telephone switched network using DTMF telephone signals, wherein a number of appliances are TV appliances, said system comprising:

a like plurality of internal tone control devices, each for decoding a sequence of DTMF signals, verifying if said sequence of DTMF signals coincides with a preset identification code and converting said sequence into a control signal;

a like number of receiving-switching units each associated with a TV appliance and with an associated internal tone control device, for receiving said control signal from said associated internal tone control device and for selectively coupling the associated TV appliance to a conventional TV cable network and to an optical fiber TV cable network according to said control signal;

means for connecting each of said internal tone control devices to the telephone switched network for receiving said sequence of DTMF signals and transferring it to said internal tone control devices;

means for coupling each of said receiving-switching units to the conventional TV cable network and to the optical fiber TV cable network; and

means for transmitting said control signal from said internal tone control device to the non-TV appliances for activating/deactivating the non-TV appliances with said control signal wherein said internal tone control devices comprise;

an overvoltage protection and d.c. insulation unit for receiving said sequence of DTMF signals;

a DTMF decoder connected to said overvoltage protection and insulation unit, for decoding a first and a second signal from said sequence of DTMF signals and generating a first and a second digit therefrom;

a first digit detector having a first identification code, connected to said DTMF decoder for comparing said first identification code to said first digit and producing a first digit valid signal;

a second digit decoder having a second identification code, connected to said DTMF decoder for comparing said second identification code to said second digit and producing a said second digit valid signal;

a memory unit, connected to said first digit detector for storing said first digit;

a logic unit connected to said second digit detector and to said memory unit, for determining if said sequence of said first and second digits is valid and generating said d.c. control signal; and

a delay timer unit for resetting said memory if said second digit valid signal is not produced after a predetermined time.

2. A system as claimed in claim 1, wherein said means for coupling comprises:

a TV cable splitter for connecting the conventional TV cable network to each receiving-switching unit; and

an optical fiber cable splitter for connecting the optical fiber TV cable network to each receiving-switching unit.

3. A system for controlling a TV appliance at a station which is connected to a telephone switched network using DTMF telephone signals comprising:

P1 an internal tone control device, for decoding a sequence of DTMF signals, verifying if said sequence of DTMF signals coincides with a preset, identification code and converting said sequence into a control signal;

a receiving-switching unit for receiving said control signal from said internal tone control device and for selectively coupling the TV appliance to a conventional TV cable network and to an optical fiber TV cable network according to said control signal;

means for connecting said internal tone control device to the telephone switched network for receiving said sequence of DTMF signals and transferring it to said internal tone control device; and

means for coupling said receiving-switching unit to the conventional TV cable network and to the optical fiber TV cable network wherein said internal tone control device comprises;

an overvoltage protection and d.c. insulation unit for receiving said sequence of DTMF signals;

a DTMF decoder connected to said overvoltage protection and insulation unit, for decoding a first and a second signal from said sequence of DTMF signals and generating a first and a second digit therefrom;

a first digit detector having a first identification code, connected to said DTMF decoder for comparing said first identification code to said first digit and producing a first digit valid signal;

a second digit detector having a second identification code, connected to said DTMF decoder for comparing said second identification code to said second digit and producing a said second digit valid signal;

a memory unit, connected to said first digit detector for storing said first digit;

a logic unit connected to said second digit detector and to said memory unit, for determining if said sequence of said first and second digits is valid and generating said control signal; and

a delay timer unit for resetting said memory if said second digit valid signal is not produced after a predetermined time.

4. A system as claimed in claim 3, wherein said receiving switching device comprises:

a first connector for receiving an incoming TV cable;

a second connector for coupling said receiving switching device with the TV appliance;

a third connector for connecting said internal control tone device;

an optical receiver for connecting an optical fiber TV cable and for converting the optical signal received on said optical fibre cable into an electric TV signal;

a relay including a relay switch connected to connect said optical receiver and said first connector to said second connector, and a relay coil for actuating said relay switch; and

a NPN transistor connected with the base to said third connector for receiving said control signal, the emitter connected to the ground and the collector connected through said relay coil to a d.c. positive power supply.

5. A system as claimed in claim 3, further comprising a reset timer unit for resetting said memory unit and said logic unit during a preset time delay after power is supplied to said internal tone control device.

6. A system as claimed in claim 5, wherein said time delay is 0.5 seconds.

7. A system as claimed in claim 3, wherein said predetermined time is 1.5 seconds.

8. A system as claimed in claim 3, wherein said delay timer unit resets said memory unit after each processing of a sequence of said first and second digits.

9. A system as claimed in claim 3, wherein said first digit detector comprises:

a first switch array for presetting said first identification code; and

an AND circuit for producing said first digit valid signal when each bit of said first digit coincides with a corresponding bit of said first identification code.

10. A system as claimed in claim 9, wherein said second digit detector comprises:

a second switch array for presetting said second identification code; and

an AND circuit for producing said second digit valid signal when each bit of said second digit coincides with a corresponding bit of said second identification code.

11. A system as claimed in claim 10, wherein each said first and said second switch arrays comprise a multitude of switch-inverter pairs for producing a direct and an inverted input according to said switch array configuration and applying it to said AND gate.

12. A system as claimed in claim 3, wherein said DTMF signal decoder detects if said sequence of DTMF signals appertains to the telephone switched network and accordingly generates a valid DTMF signal.

13. A system as claimed in claim 3, wherein said DTMF decoder generates said first and said second digits in a four bit format.

14. A system as claimed in claim 3, wherein said first digit memory comprises a first JK flip-flop for storing said first digit valid signal for said predetermined time.

15. A system as claimed in claim 3, wherein said delay timer unit comprises a first voltage comparator having a first input connected to a first resistive divider and a second input connected to a first integrator for generating a validating signal to said logic unit and said memory unit when the voltage on said second input exceeds the voltage on said first input.

16. A system as claimed in claim 3, wherein said logic unit comprises a second JK flip-flop and a NAND gate connected to the clock input of said second flip-flop for generating said control signal when said first digit valid signal and said second digit valid signal are present at the inputs of said NAND gate.

17. A system as claimed in claim 5, wherein said reset timer unit comprises a second voltage comparator having a first input connected to a second resistive divider and a second input connected to a second integrating circuit such that said memory unit and said logic unit are maintained in a reset state when the voltage on said second input exceeds the voltage on said first input.

18. A system as claimed in claim 3, wherein said overvoltage protection and d.c. insulation unit comprises two back to back zener diodes connected between the telephone lines and an insulating capacitor connected in series with each telephone line.