Computer signal transmission system

• US 6,618,774 B1
• Filed: 03/16/2000
• Issued: 09/09/2003
• Est. Priority Date: 03/17/1999
• Status: Expired due to Term

• Current Assignee: Adder Technology Limited
• Original Assignee: Adder Technology Limited
• Inventors: Hudson, Philip Edward, Dickens, Adrian Christopher, Dickens, Nigel Anthony
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): Mai, Rijue
• Application Number:
  US09/527,067
• Time in Patent Office: 1,272 Days
• Field of Search: 710/1, 710/15, 710/20, 710/39, 710/51, 710/72, 710/107, 710/63, 710/64, 710/126, 710/128, 710/17, 710/38, 710/62, 455/3.1, 348/7, 725/51, 725/40, 345/327, 174/19, 174/27
• US Class Current: 710/64
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices
• CPC Class Codes: G09G 2370/045 using multiple communication channels, e.g. parallel and serial
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: H04L 5/02 Channels characterised by the type of signal
• CPC Class Codes: H04N 11/00 Colour television systems details H04N9/00
• CPC Class Codes: H04N 17/00 Diagnosis, testing or measuring for television systems or their details
• CPC Class Codes: H04N 5/60 for the sound signals
• CPC Class Codes: H04N 7/108 the cable being constituted by a pair of wires

Abstract

A system for transmitting electrical signals between a computer and peripherals along a twisted pair cable. The system includes a computer interface, a peripheral interface and a twisted pair cable in communication between the computer interface and the peripheral interface. Video and audio signals from the computer are transmitted via the twisted pair cable to the peripherals. Peripheral signals can also be communicated between the computer and peripherals via the twisted pair cable.

Claims

1. A system for transmitting electrical signals between a computer and peripherals along a twisted pair cable, comprising:

a computer interface;

a multiplexer associated with the computer interface;

a peripheral interface; and

a twisted pair cable including a plurality of twisted pair lines, the twisted pair cable being in communication between the computer interface and the peripheral interface, in which a red, a green and a blue video colour signal, a horizontal and a vertical video syuchronisation signal and at least one audio signal from the computer are transmitted via three twisted pair lines of the cable to the peripherals via the peripheral interface, and in which the multiplexer multiplexes one of the video synchronization signals and either one of the video colour signals, or said at least one audio signal, for transmission via one of the three twisted pair lines.

2. A system as claimed in claim 1, in which a one of the video colour signals, a one of the video synchronisation signals and the audio signal are all transmitted via a one of the three twisted pair lines.

3. A system as claimed in claim 1, in which a second audio signal is also transmitted via a one of the three twisted pair lines of the cable.

4. A system as claimed in claim 1, in which peripheral signals are transmitted between the computer and peripherals via a fourth twisted pair line of the cable.

5. A system as claimed in claim 1, in which further audio signals are transmitted between the peripherals and the computer via a fourth twisted pair line of the cable.

6. A system as claimed in claim 1, in which:

a first of the video colour signals and the vertical video synchronisation signal are transmitted along a first twisted pair line;

a second of the video colour signals, the horizontal video synchronisation signal and a first audio signal are transmitted along a second twisted pair line; and

a third of the video colour signals, the horizontal video synchronisation signal and a second audio signal are transmitted along a third twisted pair line.

7. A system as claimed in claim 1, in which the video signals provide a video input to a video display unit and the audio signal provides an audio input to an audio output device.

8. A system as claimed in claim 1, in which the multiplexer multiplexes one of the video colour signals and one of the video synchronisation signals for transmission by a twisted pair line.

9. A system as claimed in claim 1, in which the multiplexer multiplexes the audio signal and one of the video synchronisation signals for transmission by a twisted pair line.

10. A system as claimed in claim 9, and including a sampler which samples the audio signal to be multiplexed.

11. A system as claimed in claim 9, in which the multiplexer also multiplexes a video colour signal.

12. A system as claimed in claim 9, and including a second multiplexer which muliplexes a second audio signal and a one of the video synchronisation signals for transmission by a second twisted pair line.

13. Apparatus for transmitting a multiplexed video synchronisation signal and an audio signal from a computer to a video display unit and an audio output, comprising:

a signal combiner which receives a video synchronisation signal from a video output of a computer;

a sampler which samples the audio signal and communicates the sampled audio signal to the signal combiner;

a twisted pair cable connected at a first end to the signal combiner; and

a signal separator connected to a second end of the twisted pair cable, in which the signal combiner modulates the amplitude of the video synchronisation signal with the sampled audio signal and the signal separator provides separate transmitted video synchronisation and audio signals to the video display unit and the audio output respectively.

14. Apparatus as claimed in claim 13, in which video synchronisation signal is used to gate the sampling of the audio signal.

15. Apparatus as claimed in claim 13, in which the signal combiner also receives a video colour signal from the video output of the computer and the signal combiner periodically adds the amplitude modulated video synchronisation signal to the video colour signal when the video colour signal is inactive and the signal separator provides separate transmitted video colour and video synchronisation signals to the video display unit.

16. Apparatus as claimed in claim 13, in which the video synchronisation signal is a horizontal synchronisation signal.

17. Apparatus as claimed in claim 15, in which the video synchronisation signal and the video colour signal have opposite polarity.

18. Apparatus as claimed in claim 15, in which the added video synchronisation signal has negative polarity.

19. Apparatus as claimed in claim 13, and including a polarity detector and a polarity converter in communication with the signal combiner which detect the polarity of the video sychronisation signal received from the computer and transmit only a video synchronisation signal having a particular polarity to the signal combiner.

20. Apparatus as claimed in claim 19, and including a polarity restorer in communication with the signal separator which controls the polarity of the video synchronisation signal supplied to the video display unit to be appropriate for the video display unit.

21. Apparatus as claimed in claim 20, and including video synchronisation timing signal transmission means which transmits a timing signal derived from the polarity detector to the polarity restorer to coordinate the polarity of the video synchronisation signal supplied by the computer video output and the polarity of the video synchronisation signal supplied to the video display unit.

22. Apparatus as claimed in claim 13 and including an amplifier receiving the transmitted multiplexed signal and amplifying it to compensate for transmission degradation.

23. A system for transmitting electrical signals between a computer and peripherals along a twisted pair cable, comprising:

a computer interface;

a multiplexer associated with the computer interface

a peripheral interface; and

a twisted pair cable in communication between the computer interface and the peripheral interface, in which said multiplexer multiplexes a video synchronisation signal and either a video colour signal or an audio signal from the computer so that the video synchronisation signal, the video color signal and the audio signal are transmitted via a single twisted pair line of the twisted pair cable to the peripherals.

24. A system as claimed in claim 23, in which the audio signal is encoded by the video synchronisation signal.

25. A system as claimed in claim 24, in which the audio signal is encoded by amplitude modulation of the video synchorisation signal.

26. A system as claimed in claim 25, in which the video synchronisation signal is a horizontal video synchronisation signal.

27. A method for transmitting electrical signals between a computer interface and a peripheral interface, comprising:

providing a twisted pair cable connected between the computer interface and the peripheral interface, the twisted pair cable including a plurality of twisted pair lines;

multiplexing a horizontal or a vertical synchronization signal and either a red, green or blue video colour signal or at least one audio signal; and

transmitting the red, green and blue video colour signals, the horizontal and a vertical video synchronisation signals and the audio signal from the computer interface to the peripheral interface via three twisted pair lines of the cable.

28. A method for transmitting electrical signals between a computer interface and a peripheral interface, comprising:

providing a twisted pair cable connected between the computer interface and the peripheral interface;

multiplexing a video synchronisation signal and either a video colour signal or an audio signal and

transmitting the video colour signal, the video synchronisation signal and the audio signal from the computer interface to the peripheral interface via a single twisted pair line of the cable.