User manual

Cables

NXA-ENET24 Hardware Installation Guide

Crossover Wiring

If the twisted-pair cable is to join two ports and either both ports are labeled with an “X” (MDI-X) or

neither port is labeled with an “X” (MDI), a crossover must be implemented in the wiring. (When auto-

negotiation is enabled for any RJ-45 port on this switch, you can use either straight-through or crossover

cable to connect to any device type.)

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.

Cables must also pass test parameters for Return Loss and Equal-Level Far-End Crosstalk (ELFEXT).

These tests are specified in the ANSI/TIA/EIA-TSB-95 Bulletin, “The Additional Transmission

Performance Guidelines for 100 Ohm 4-Pair Category 5 Cabling.”

FIG. 26 Crossover Wiring

1000BASE-T MDI-X and MDI Port Pinouts

Pin MDI-X Signal Name MDI Signal Name

1 Bi-directional Data Two Plus (BI_D2+) Bi-directional Data One Plus (BI_D1+)

2 Bi-directional Data Two Minus (BI_D2-) Bi-directional Data One Minus (BI_D1-)

3 Bi-directional Data One Plus (BI_D1+) Bi-directional Data Two Plus (BI_D2+)

4 Bi-directional Data Four Plus (BI_D4+) Bi-directional Data Three Plus (BI_D3+)

5 Bi-directional Data Four Minus (BI_D4-) Bi-directional Data Three Minus (BI_D3-)

6 Bi-directional Data One Minus (BI_D1-) Bi-directional Data Two Minus (BI_D2-)

7 Bi-directional Data One Plus (BI_D3+) Bi-directional Data One Plus (BI_D4+)

8 Bi-directional Data Three Minus (BI_D3-) Bi-directional Data Four Minus (BI_D4-)

White/Orange Stripe

Orange

White/Green Stripe

Green

EIA/TIA 568B RJ-45 Wiring Standard

10/100BASE-TX Crossover Cable

End A

End B

White/Brown Stripe

Brown Stripe

Blue

White/Blue Stripe