Method and apparatus for providing low power basic telephony type service over a twisted pair ethernet physical layer

• US 5,805,597 A
• Filed: 06/04/1996
• Issued: 09/08/1998
• Est. Priority Date: 06/04/1996
• Status: Expired due to Term

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Edem, Brian
• Primary Examiner(s): NGUYEN, CHAU T
• Application Number:
  US08/660,334
• Time in Patent Office: 826 Days
• Field of Search: 370/465, 370/466, 370/476, 370/498, 370/552, 370/524, 370/445, 370/446, 370/458, 370/459, 370/460, 370/434, 370/401, 370/404, 340/825.5, 340/825.06, 340/825.05, 455/527, 455/574
• US Class Current: 370/445
• CPC Class Codes: H04L 12/44 Star or tree networks
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6427 Subscriber Access Module; Concentrator; Group equipment
• CPC Class Codes: H04L 2012/6437 Ring
• CPC Class Codes: H04L 2012/6454 Random, e.g. Ethernet
• CPC Class Codes: H04L 2012/6459 Multiplexing, e.g. TDMA, CDMA
• CPC Class Codes: H04L 2012/6475 N-ISDN, Public Switched Telephone Network [PSTN]

Abstract

A network communication system having at least two communication protocol modes, namely, a full power communication mode and a low power, limited communication mode. In the low power mode, the link is line powered and utilizes link pulses to represent binary 1s and idle line states to represent binary 0s so that low power mode communication is entirely compatible with all 10BASE T equipment on the network.

Claims

1. A method of providing a low power digital communication protocol between first and second communication endpoints over an ethernet physical layer, said method comprising the steps of:

generating digital data at said first endpoint, said digital data comprising a plurality of bit groups representing a communication signal at an instant in time, each of said bit groups comprising a plurality of bits;

periodically organizing each of said bit groups into a serial bit stream;

periodically converting each of said organized bit groups into a repeating frame template, said frame template comprising a bit slot corresponding to each bit of said organized bit group, in which each bit of said organized bit group is represented by the presence or absence of an ethernet link pulse in said corresponding bit slot; and

periodically transmitting said frame template from said first endpoint to said second endpoint.

2. The method of claim 1 wherein said digital data comprises multiple channels of data.

3. The method of claim 2 wherein said digital data comprises two voice channels and a signalling channel.

4. The method of claim 1 wherein binary zeroes are represented in said frame template as the absence of a link pulse in the corresponding bit slot and binary ones are represented by link pulses in the corresponding bit slots.

5. The method of claim 4 wherein alternate ones of said binary ones are represented by link pulses of alternate polarity in the corresponding bit slots.

6. The method of claim 5 wherein said frame template further comprises an end bit slot and wherein the step of converting said data into said frame template further comprises the step of placing a link pulse of polarity opposite the polarity of the preceding link pulse in said frame template when said template otherwise comprises an odd number of link pulses.

7. The method of claim 6 wherein said frame template further comprises a start bit slot containing a link pulse positioned at the beginning of said frame template and wherein said frame template comprises all of said bit slots grouped together in close temporal proximity followed by an idle period greater in duration than a duration of all of said bit slots.

8. The method of claim 7 wherein said link pulses are 100 nanoseconds in duration and said bit slots are 1 microsecond in duration.

9. The method of claim 8 wherein said digital data comprises a first data channel comprising 8 bits, a second data channel comprising 8 bits and a signalling channel comprising 8 bits and wherein said frame template is repeated every 125 microseconds.

10. The method of claim 9 wherein said frame template comprises 26 consecutive bit slots followed by 99 microseconds of idle time.

11. The method of claim 1 wherein said first endpoint is capable of communicating in a full power protocol having greater bandwidth than said low power protocol and further comprising the steps of;

generating a low power request signal when said first endpoint is operating in said full power protocol and data traffic at said first endpoint is not greater than that which can be transmitted within said frame template;

transmitting said low power request signal to said second endpoint;

detecting a low power acknowledge signal from said second endpoint indicating that said second endpoint can operate in said low power protocol; and

means for switching from said full power protocol to said low power protocol responsive to receipt of said low power acknowledge signal.

12. The method of claim 1 wherein said ethernet physical layer comprises a twisted pair.

13. A network apparatus for providing a low power digital communication protocol between multiple communication endpoints over an ethernet physical layer comprising:

first and second communication endpoints;

an ethernet physical layer interconnecting said first and second communication endpoints;

a data source coupled to said first endpoint for generating digital data, said digital data comprising a plurality of bit groups representing a communication signal at an instant in time, each of said bit groups comprising a plurality of bits;

an encoder/serializer, coupled to receive said data from said data source, for organizing each of said bit groups into a serial bit stream;

a link pulse generator, coupled to receive said bit stream, for converting each of said organized bit groups into a frame template, said frame template comprising a bit slot corresponding to each bit of said organized bit group, in which each bit of said organized bit group is represented by the presence or absence of an ethernet link pulse in said corresponding bit slot; and

a transmitter for transmitting said frame template from said first endpoint to said second endpoint.

14. The network apparatus of claim 13 wherein said digital data comprises two voice channels and a signalling channel of data.

15. The network apparatus of claim 14 wherein said digital data comprises an ISDN data stream.

16. The network apparatus of claim 13 wherein said link pulse generator generates a link pulse corresponding to each binary one in said bit stream and maintains line voltage for each binary zero in said bit stream.

17. The network apparatus of claim 16 wherein said link pulse generator generates a link pulse of opposite polarity for alternate binary ones in said data stream.

18. The network apparatus of claim 17 wherein said frame template further comprises a start bit slot and an end bit slot and said encoder/serializer further comprises timing and control circuitry for inserting a binary one bit at the beginning of said bit stream corresponding to said start bit slot and for inserting a binary one at the end of said bit stream when a number of binary ones in said frame template is an odd number.

19. The network apparatus of claim 18 wherein said timing and control circuitry causes said bit stream to be sent to said link pulse generator followed by an idle period greater in duration than a duration of said bit stream before a next bit stream is sent to said link pulse generator.

20. The network apparatus of claim 19 wherein said link pulses are 100 nanoseconds in duration and said bit slots are 1 microsecond in duration.

21. The network apparatus of claim 20 wherein said digital data comprises a first data channel comprising 8 bits per frame template, a second data channel comprising 8 bits per frame template and a maintenance channel comprising 8 bits per frame template and wherein said frame template is repeated every 125 microseconds.

22. The network apparatus of claim 21 wherein said frame template comprises 26 consecutive bit slots followed by 99 microseconds of idle time.

23. The network apparatus of claim 13 wherein said first endpoint further comprises circuitry for providing communication in accordance with a full power protocol providing greater bandwidth than said frame template, said apparatus further comprising;

means for generating a low power request signal when said first endpoint is operating in said full power protocol and data traffic at said first endpoint is not greater than that which can be transmitted within said frame template;

means for transmitting to said second endpoint said low power request signal;

means for detecting a low power acknowledge signal from said second endpoint indicating that said second endpoint can operate in said low power protocol; and

means for switching from said full power protocol to said low power protocol responsive to receipt of said low power acknowledge signal.

24. The network apparatus of claim 13 wherein said ethernet physical layer comprises a twisted pair.

25. A network endpoint capable of communicating in a low power digital communication protocol over an ethernet physical layer comprising:

a data source coupled to said endpoint for generating digital data, said digital data comprising a plurality of bit groups representing a communication signal at an instant in time, each of said bit groups comprising a plurality of bits;

an encoder/serializer, coupled to receive said data from said data source, for organizing each of said bit groups into a serial bit stream;

a link pulse generator, coupled to receive said bit stream, for converting each of said organized bit groups into a frame template, said frame template comprising a bit slot corresponding to each bit of said organized bit group, in which each bit of said organized bit group is represented by the presence or absence of an ethernet link pulse in said corresponding bit slot; and

a transmitter for transmitting said frame template from said first endpoint to said second endpoint.

26. The network endpoint of claim 25 further comprising;

a data sink coupled to said endpoint for receiving digital data, said digital data comprising a plurality of bit groups representing a communication signal at an instant in time, each of said bit groups comprising a plurality of bits;

a receiver for receiving said frame template from another endpoint over said twisted pair ethernet physical layer;

a link pulse detector, coupled to receive said frame template from said receiver, for detecting link pulses; and

a decoder/deserializer, coupled to receive said series of link pulses from said link pulse detector, for converting said series of link pulses into a parallel bit stream.

27. The network endpoint of claim 26 wherein said link pulse generator generates a link pulse corresponding to each binary one in said bit stream and maintains line voltage for each binary zero in said bit stream.

28. The network endpoint of claim 27 wherein said link pulse generator generates a link pulse of opposite polarity for alternate binary ones in said data stream.

29. The network endpoint of claim 28 wherein said frame template further comprises a start bit slot and an end bit slot and said encoder/serializer further comprises timing and control circuitry for inserting a binary one bit at the beginning of said bit stream corresponding to said start bit slot and for inserting a binary one at the end of said bit stream when a number of binary ones in said frame template otherwise is an odd number.

30. The network endpoint of claim 29 wherein said timing and control circuitry causes said bit stream to be sent to said link pulse generator followed by an idle period greater in duration than a duration of said bit stream before a next bit stream is sent to said link pulse generator.

31. The network endpoint of claim 30 wherein said frame template comprises 26 consecutive bit slots followed by 99 microseconds of idle time.