Nortel Networks 1000BASE-ZX Manual Do Utilizador

Appendix D Connectors and pin assignments

209418-A

 lists the RJ-45 (8-pin modular) port connector pin assignments.

Media dependent interface (MDI) is the IEEE standard for the interface to 
unshielded twisted pair (UTP) cable.

For two devices to communicate, the transmitter of one device must connect to the 
receiver of the other device. The connection is established through a crossover 
function, which can be a crossover cable or a port that implements the crossover 
function internally.

Ports that implement the crossover function internally are known as MDI-X ports, 
where X refers to the crossover function.

The following sections describe the use of straight-through and crossover cables 
for connecting MDI and MDI-X devices.

Table 54   RJ-45 port connector pin assignments

1

RX+

Receive  Data  +

2

RX-

Receive  Data  -

3

TX+

Transmit Data +

4

Not applicable

Not applicable

5

Not applicable

Not applicable

6

TX-

Transmit Data -

7

Not applicable

Not applicable

8

Not applicable

Not applicable

Note: For the transmitter of one device to connect to the receiver of 
another device, the total number of crossovers must always be an odd 
number.