There are two accepted standards for 8-wire data network jacks (commonly and
incorrectly called "RJ-45.")
ANSI/TIA/EIA-568-B "Commercial Building
Telecommunications Cabling Standard" lists both wiring configurations. T568B is
the most prevalent for commercial installations, and was used by AT&T for the
original Merlin phone systems. To help you remember, associate "B" with "Bell."
ANSI/TIA/EIA-570-B "Residential Telecommunications Cabling Standards"
- If the installation is residential, choose T568A unless other conditions
apply (see below). The two inner pairs of 568A are wired the same as a two-line
- If there is pre-existing voice/data wiring (remodel, moves, adds, changes),
duplicate this wiring scheme on any new connection.
- If project specifications are available, use the specified wiring
- If components used within the project are internally wired for either T568A or
T568B, use that wiring scheme.
- Make sure both ends of a cable are wired the same way.
|Jack Wiring |
(Based on info from Leviton)