Bay Technical Associates 350 사용자 설명서
Using the BayStack 350 10/100 Autosense Switch
B-2
893-00992-B
MDI and MDI-X Devices
Media Dependent Interface (MDI) is the IEEE standard for the interface to
unshielded twisted pair (UTP) cable.
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.
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.
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.
for connecting MDI and MDI-X devices.
Table B-1.
RJ-45 port connector pin assignments
Pin
Signal
Description
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.
350fbk.book Page 2 Wednesday, July 9, 1997 4:51 PM