Network system for linking user nodes using high speed CSMA/CD communication

• US 5,852,635 A
• Filed: 03/31/1997
• Issued: 12/22/1998
• Est. Priority Date: 01/25/1994
• Status: Expired due to Fees

• Current Assignee: LAN Media Corp (Neonode, Inc.)
• Original Assignee: Ronald C. Crane
• Inventors: Crane, Ronald C.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): GHAYOUR, MOHAMMAD H
• Application Number:
  US08/831,280
• Time in Patent Office: 631 Days
• Field of Search: 375/264, 375/286, 341/50, 341/57, 341/58
• US Class Current: 375/264
• CPC Class Codes: H03M 1/66 Digital/analogue converters H03M1/001 – H03M1/10 take precedence
• CPC Class Codes: H04L 12/40013 Details regarding a bus controller
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• CPC Class Codes: H04L 12/44 Star or tree networks

Abstract

An Ethernet-type local area network having multiport repeaters and nodes within a specified distance of the hub is able to communicate high speed digital data over multiple pairs of twisted-pair wires using long symbol group-type ternary coding. Bundle mode termination minimize impedance mismatches. Low-frequency collision detection circuitry permits detection of packet collisions on an a.c.-coupled network. Precise serialized digital to analog conversion is realized using chains of gates to form delay elements with precise delays.

Claims

1. A local area network communicating CSMA/CD data over a medium comprising:

a plurality of nodes interconnected via a communication medium;

an 8B6T encoding means at each node for applying a long-term d.c.-balanced three-level communication signal containing information to the communication medium, said signal applying means receiving group codes in binary form of eight units length and converting each eight-bit group to a three-level ternary code of groups of six units length, said ternary code consisting of selected d.c.-balanced six-unit symbol groups, selected plus-one-biased d.c.-unbalanced six-unit symbol groups and selected minus-one-biased d.c.-unbalanced six-unit symbol groups, and said signal applying means being operative to constrain signals to enforce a d.c. polarity reversal after transmission of each d.c.-unbalanced group; and

an 8B6T decoding means at each node for receiving the long-term d.c.-balanced three-level communication signal from the communication medium and converting three-level information of said long-term d.c.-balanced three-level communication signal to corresponding eight-bit group binary level code by assuming a long-term d.c. balance.

2. A local area network communicating CSMA/CD data over a medium comprising:

a plurality of nodes interconnected via a communication medium;

an 8B6T encoding means at each node for applying a long-term d.c.-balanced three-level communication signal containing information to the communication medium, said signal applying means receiving group codes in binary form of eight units length and converting each eight-bit group to a three-level ternary code of groups of six units length, and said signal applying means being operative to constrain signals to enforce a d.c. polarity reversal after transmission of each d.c.-unbalanced group, wherein said encoding means includes means for converting the eight-bit binary groups to twelve-bit binary groups, the twelve-bit binary groups having a one-for-one correspondence with each of the selected six-bit ternary code groups; and

an 8B6T decoding means at each node for receiving the long-term d.c.-balanced three-level communication signal from the communication medium and converting three-level information of said long-term d.c.-balanced three-level communication signal to corresponding eight-bit group binary level code by assuming a long-term d.c. balance.

3. A local area network communicating CSMA/CD data over a medium comprising:

a plurality of nodes interconnected via a communication medium;

an 8B6T encoding means at each node for applying a long-term d.c.-balanced three-level communication signal containing information to the communication medium, said signal applying means receiving group codes in binary form of eight units length and converting each eight-bit group to a three-level ternary code consisting of 256 six-unit length symbol groups selected from all six-unit symbol groups having

a) a d.c. balance of 0, or

b) a d.c. unbalance of +1 or

c) d.c. unbalance of -1, and excluding

d) any six-unit length symbol group having no transitions, and wherein said signal applying means is operative to constrain signals to enforce a d.c. polarity reversal after transmission of each d.c.-unbalanced group; and

an 8B6T decoding means at each node for receiving the long-term d.c.-balanced three-level communication signal from the communication medium and converting three-level information of said long-term d.c.-balanced three-level communication signal to corresponding eight-bit group binary level code by assuming a long-term d.c. balance.