HP NC3122 Fast Ethernet Server Adapter - Manual (Page 18)

C-2 Compaq NC3122 Fast Ethernet Server Adapter User Guide
UTP Cable Specifications
To connect to the network, the NC3122 adapter uses the following cable.
10BASE-T
■ Category 3 or better UTP twisted-pair
■ 22-26 AWG, 100
Ω at 1MHz
■ EIA/TIA 568a or EIA/TIA 568b
100BASE-T
■ Category 5 or better UTP twisted pair
■ 22-26 AWG, 100
Ω at 1MHz
■ EIA/TIA 568a or EIA/TIA 568b
RJ-45 Pinouts and Crossover Function
10BASE-T and 100BASE-TX are keyed systems to differentiate between voice and data
transmissions, in order to keep them separate over twisted-pair cable. The Ethernet standard also
specifies that each cable 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/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