Asynchronous integrated voice and data communication system

• US 4,450,554 A
• Filed: 08/10/1981
• Issued: 05/22/1984
• Est. Priority Date: 08/10/1981
• Status: Expired due to Term

• Current Assignee: ITT Corporation (ITT, Inc.)
• Original Assignee: International Telephone & Telegraph Corp. (ITT, Inc.)
• Inventors: Finley, Thomas E., Steensma, Peter D., Smid, Robert W., Weinberg, Murray
• Primary Examiner(s): Briganee, Gerald L.
• Application Number:
  US06/291,690
• Time in Patent Office: 1,016 Days
• Field of Search: 370/1, 370/2, 370/3, 370/4, 370/41, 370/42, 370/60, 370/86, 370/91, 370/94, 370/80
• US Class Current: 398/54
• CPC Class Codes: H04B 10/50 Transmitters
• CPC Class Codes: H04L 12/44 Star or tree networks
• CPC Class Codes: H04L 12/64 Hybrid switching systems
• CPC Class Codes: H04M 11/068 using time division multiplex techniques; integrated services digital networks H04Q11/0428

Abstract

The asynchronous integrated voice and data communication system includes a continuously variable slope delta encoder and a continuously variable slope delta decoder to convert voice signals to coded signals and vice versa. A packetizer and a depacketizer are employed with each data and voice user to enable each of the plurality of data and voice users to have random access to a fiber optic transmission medium enabling each of the plurality of data and voice users to receive transmissions from all others of the plurality of users. A microcomputer is coupled to each of the voice and data users and the associated packetizer and depacketizer to enable any one of the plurality of data and voice users to establish communication with any other selected one of the plurality of data and voice users.

Claims

1. An asynchronous integrated voice and data communication system comprising:

a plurality of data users;

a plurality of voice users;

a fiber optic transmission medium enabling each of said plurality of data and voice users to receive packet type transmissions from all others of said plurality of data and voice users at any completely random time;

a plurality of first means each coupled to a different one of said plurality of voice users to convert voice signals to coded signals and vice versa;

a plurality of second means each coupled to said transmission medium, certain ones of said plurality of second means each being coupled to certain ones of said plurality of second means each being coupled to a different one of said plurality of first means and other ones of said plurality of second means each being coupled to a different one of said plurality of data users to enable each of said plurality of data and voice users to have completely random pocket type access to said transmission medium at any time; and

a plurality of third means each coupled to a different one of said second means and an associated one of said plurality of data and voice users to enable any one of said plurality of data and voice users to establish communication with any other selected one of said plurality of data and voice users at any completely random time.

2. A system according to claim 1, wherein

said transmission medium includes a star coupler coupled to each of said second means.

3. A system according to claim 2, wherein

each of said plurality of first means includes

a continuously variable slope delta encoder coupled to an associated one of said plurality of voice users to convert voice signals to delta coded signals, and

a continuously variable slope delta decoder coupled to said associated one of said plurality of voice users to convert received delta coded signals addressed to said associated one of said plurality of voice users to voice signals.

4. A system according to claim 3, wherein

each of said plurality of second means includes

a packetizer coupled to said transmission medium and an associated one of said plurality of data users and said delta encoders to assemble input signals thereto into sequential first packets each having a predetermined length, to transmit each of said first packets in a random manner to said transmission medium and to wait until each of said first packets are returned from said transmission medium before transmitting a succeeding one of said first packets to said transmission medium, and

a depacketizer coupled to said transmission medium and an associated one of said plurality of data users and said delta decoders to identify and check each of said returned first packets for errors, to inform said packetizer when each of said returned first packets are acceptable to enable said packetizers to assemble and transmit said succeeding one of said first packets, to identify received second packets having said predetermined length addressed to said associated one of said plurality of data and voice users from another of said plurality of data and voice users and to pass said received second packets to said associated one of said plurality of data users and said delta decoders,

said packetizer responding to said depacketizer detecting unacceptable ones of said first packets to retransmit said unacceptable one of said first data packets to said transmission medium.

5. A system according to claim 4, wherein

said first and second packets are Manchester encoded for ease of error detection and ease of identifying idle periods at least in said voice signals, said idle periods being suppressed for transmission and later inserted after reception.

6. A system according to claim 4, wherein

each of said first and second packets includes

a first preamble portion having therein an origination address and a destination address to which said depacketizer responds, and

a first information portion following said first preamble portion.

7. A system according to claim 6, wherein

at least said first information portion is Manchester encoded for ease of error detection and ease of identifying idle periods at least in said voice signals, said idle periods being suppressed for transmission and later inserted after reception.

8. A system according to claim 6, wherein

said first preamble portion is generated separate from said first information portion, said first information portion being inserted after said first preamble portion in a shift register.

9. A system according to claim 8, wherein

at least said first information portion is Manchester encoded for ease of error detection.

10. A system according to claims 4, 6 or 8, wherein

said packetizer assembles said input signals in parallel form and transmits said first packets to said transmission medium in serial form, and

said depacketizer operates on said first and second packets in parallel form and provides an output signal therefrom in serial form.

11. A system according to claim 10, wherein

each of said third means includes a microcomputer coupled to said packetizer, said depacketizer and an associated one of said plurality of data and voice users.

12. A system according to claim 11, wherein

each of said microcomputers includes a microprocessor to provide signaling information in the form of first digital control words for coupling to said packetizer and to receive signal information in the form of second digital control words from said depacketizer to establish communication between an associated one of said plurality of data and voice users and any other selected one of said plurality of data and voice users.

13. A system according to claim 12, wherein

said first and second code words are Manchester encoded for ease of error detection.

14. A system according to claim 12, wherein

said first and second digital control words include a second preamble portion identical to said first preamble portion and a second information portion having a length less than the length of said first information portion.

15. A system according to claim 14, wherein

said first control words are retransmitted by said packetizer at predetermined time intervals provided no first packets are to be sent.

16. A system according to claim 15, wherein

said depacketizer includes fourth means to distinguish between said first and second packets and said second code words based on the length thereof.

17. A system according to claim 16, wherein

said second information portion is Manchester encoded for ease of error detection.

18. A system according to claim 15, wherein

said second information portion is Manchester encoded for ease of error detection.

19. A system according to claim 14, wherein

said second information portion is Manchester encoded for ease of error detection.

20. A system according to claim 4, further including

a plurality of optical transmitters each coupled between a different one of said packetizers and said transmission medium;

and

a plurality of optical receivers each coupled between a different one of said depacketizers and said transmission medium.

21. A system according to claim 20, wherein

each of said plurality of optical transmitters includes a light-emitting diode.

22. A system according to claim 20, wherein

each of said plurality of optical transmitters includes a laser source.

23. A system according to claim 22, wherein

each of said laser sources includes a laser and a low-frequency, closed loop system to stabilize the light output from said laser by varying a direct current bias current coupled to bias said laser.

24. A system according to claims 20, 21, 22 or 23, wherein

each of said plurality of optical receivers include a PIN diode.

25. A system according to claims 20, 21, 22 or 23, wherein

each of said plurality of optical receivers includes an avalanche photodiode.

26. A system according to claims 1 or 2, wherein

each of said plurality of second means includes

a packetizer coupled to said transmission medium and an associated one of said plurality of data users and encoders to assemble input signals thereto into sequential first packets each having a predetermined length, to transmit each of said first packets in a random manner to said transmission medium and to wait until each of said first packets are returned from said transmission medium before transmitting a succeeding one of said first packets to said transmission medium, and

a depacketizer coupled to said transmission medium and an associated one of said plurality of data users and decoders to identify and check each of said return first packets for errors, to inform said packetizer when each of said return first packets are acceptable to enable said packetizers to assemble and transmit said succeeding one of said first packets, to identify received second packets having said predetermined length addressed to said associated one of said plurality of data and voice users from another of said plurality of data and voice users and to pass said received second packets to said associated one of said plurality of data users and said decoders,

said packetizer responding to said depacketizer detecting unacceptable ones of said first packets to retransmit said unacceptable one of said first packets to said transmission medium.

27. A system according to claim 1, wherein

each of said plurality of first means includes

a continuously variable slope delta encoder coupled to an associated one of said plurality of voice users to convert voice signals to delta coded signals, and

a continuously variable slope delta decoder coupled to said associated one of said plurality of voice users to convert received delta coded signals addressed to said associated one of said plurality of voice users to voice signals.

28. A system according to claim 1, further including

a plurality of optical transmitters each coupled between a different one of said plurality of second means and said transmission medium;

and

a plurality of optical receivers each coupled between a different one of said plurality of second means and said transmission medium.

29. A system according to claim 28, wherein

each of said plurality of optical transmitters includes a light-emitting diode.

30. A system according to claim 28, wherein

each of said plurality of optical transmitters includes a laser source.

31. A system according to claim 30, wherein

each of said laser sources includes a laser and a low-frequency, closed loop system to stabilize the light output from said laser by varying a direct current bias current coupled to bias said laser.

32. A system according to claims 28, 29, 30 or 31, wherein

each of said plurality of optical receivers include a PIN diode.

33. A system according to claims 28, 29, 30 or 31, wherein

each of said plurality of optical receivers includes an avalanche photodiode.