C-2Compaq NC3120 Fast Ethernet Server Adapter User Guide

UTP Cable Specifications

To connect to the network, the NC3120 adapter uses the following cable.

10BASE-T

■Category 3 (or better) UTP twisted-pair

■22-26 AWG, 100Ω at 1MHz

■EIA/TIA 568a or EIA/TIA 568b

100BASE-T

■Category 5 (or better) UTP twisted pair

■22-26 AWG, 100Ω at 1MHz

■EIA/TIA 568a or EIA/TIA 568b

RJ-45 Pinouts and Crossover Function

The Ethernet standard also specifies that each segment implement a crossover function to connect the transmitter of one device to the receiver of a device at the other end, and vice-versa. The crossover function may be implemented internally at the hub or switch, or externally through the twisted-pair media.

10/100 Straight-Through Pinouts

If the crossover function is implemented internally, the port is labeled MDI-X (Medium Dependent Interface–Crossover). When an MDI-X port is connected to an MDI port, the twisted-pair media should be wired straight-through using the physical pinouts indicated in Table C-2.

Table C-2

10/100 Pinouts Using Internal, Straight-Through Crossover

Pin

Function

Color Match

Function

Pin

1

TD+

White/Orange

TD+

1

 

 

 

 

 

2

TD-

Orange/White

TD-

2

 

 

 

 

 

3

RD+

White/Green

RD+

3

 

 

 

 

 

4

 

Blue/White

 

4

 

 

 

 

 

5

 

White/Blue

 

5

 

 

 

 

 

6

RD-

Green/White

RD-

6

 

 

 

 

 

7

 

White/Brown

 

7

 

 

 

 

 

8

 

Brown/White

 

8