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Using the BayStack Model 350T 10/100 Autosense Switch
B-2
893-00992-A
Table B-1 shows the RJ-45 (8-pin modular) port connector pin assignments.
MDI and MDI-X Devices
Media Dependent Interface (MDI) is the IEEE standard for the interface to
unshielded twisted pair (UTP) cable.
For communications to take place between two devices, the transmitter of one
device must connect to the receiver of the other device. The connection must be
achieved through a crossover function, which could 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 type 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 Terminated
5 Not applicable Terminated
6 TX– Transmit Data –
7 Not applicable Terminated
8 Not applicable Terminated
Note: For the transmitter of one device to connect to the receiver of another
device, the sum of crossovers must always be an odd number.
BOOK.MKR Page 2 Tuesday, March 4, 1997 7:24 PM