Mdi And Mdi-X Devices - Nortel BayStack 350 Series Manual

Using the BayStack 350 Series 10/100 Autosense Switch
Table C-1
Table C-1.
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.
In order 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.
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.
The following sections describe the use of straight-through and crossover cables
for connecting MDI and MDI-X devices.
C-2
lists the RJ-45 (8-pin modular) port connector pin assignments.
RJ-45 port connector pin assignments
Signal
RX+
RX-
TX+
Not applicable
Not applicable
TX-
Not applicable
Not applicable
Description
Receive Data +
Receive Data -
Transmit Data +
Not applicable
Not applicable
Transmit Data -
Not applicable
Not applicable
893-00992-E