Twisted-Pair Cable and Pin Assignments
B-3
B
Figure B-3. Crossover Wiring
1000BASE-T Pin Assignments
All 1000BASE-T ports support automatic MDI/MDI-X operation, so you can use
straight-through cables for all network connections to PCs or servers, or to other
switches or hubs.
The table below shows the 1000BASE-T MDI and MDI-X port pinouts. These ports
require that all four pairs of wires be connected. Note that for 1000BASE-T
operation, all four pairs of wires are used for both transmit and receive.
Use 100-ohm Category 5, 5e or 6 unshielded twisted-pair (UTP) or shielded
twisted-pair (STP) cable for 1000BASE-T connections. Also be sure
that the length
of any twisted-pair connection does not exceed 100 meters (328 feet)
.
Cable Testing for Existing Category 5 Cable
Installed Category 5 cabling must pass tests for Attenuation, Near-End Crosstalk
(NEXT), and Far-End Crosstalk (FEXT). This cable testing information is specified in
the ANSI/TIA/EIA-TSB-67 standard. Additionally, cables must also pass test
parameters for Return Loss and Equal-Level Far-End Crosstalk (ELFEXT). These
Table B-2. 1000BASE-T MDI and MDI-X Port Pinouts
Pin MDI Signal Name MDI-X Signal Name
1 Bi-directional Data One Plus (BI_D1+) Bi-directional Data Two Plus (BI_D2+)
2 Bi-directional Data One Minus (BI_D1-) Bi-directional Data Two Minus (BI_D2-)
3 Bi-directional Data Two Plus (BI_D2+) Bi-directional Data One Plus (BI_D1+)
4 Bi-directional Data Three Plus (BI_D3+) Bi-directional Data Four Plus (BI_D4+)
5 Bi-directional Data Three Minus (BI_D3-) Bi-directional Data Four Minus (BI_D4-)
6 Bi-directional Data Two Minus (BI_D2-) Bi-directional Data One Minus (BI_D1-)
7 Bi-directional Data One Plus (BI_D4+) Bi-directional Data One Plus (BI_D3+)
8 Bi-directional Data Four Minus (BI_D4-) Bi-directional Data Three Minus (BI_D3-)
White/Orange Stripe
Orange
White/Green Stripe
Green
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
EIA/TIA 568B RJ-45 Wiring Standard
10/100BASE-TX Crossover Cable
End A
End B