Mdi And Mdi-X Devices - Nortel 325-24T Configuration Manual

426 Connectors and pin assignments
Table 164
Table 164 RJ-45 port connector pin assignments
Pin
1
2
3
4
5
6
7
8

MDI and MDI-X devices

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.
320985-A Rev 01
lists the RJ-45 (8-pin modular) port connector pin assignments.
Signal
RX+
RX-
TX+
Not applicable
Not applicable
TX-
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.
Description
Receive Data +
Receive Data -
Transmit Data +
Not applicable
Not applicable
Transmit Data -
Not applicable
Not applicable