O'Reilly logo

Local Area High Speed Networks by Dr. Sidnie Feit

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

1000BASE-T Encoding

Operating bidirectionally on twisted pairs is a challenge. The encoding used for 1000BASE-T is highly complex. It not only must achieve a balance of 0s and 1s on each cable, but it also must create a balanced electromagnetic condition across all four pairs.

The encoding method consists of several steps:

  1. Each byte is scrambled.

  2. The scrambled byte is translated to a 4-tuple of special symbols via a mapping called 8B1Q4.

  3. Each symbol is represented on the physical medium by a voltage. Five different voltage levels are used, corresponding to an alphabet of five different symbols. The physical transmission method is called 4-dimensional 5-level pulse amplitude modulation (4D-PAM5).

More details are presented in Appendix ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required