Nortel Networks 8100 manual MDI and MDI-X Connections, Figure A-1. MDI-X to MDI Cable Connections

Using the Passport 8100 Modules

MDI and MDI-X Connections

For communication 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.

The Passport 8100 modules use MDI-X ports that allow you to connect directly to end stations without using crossover cables (Figure A-1). Ports that implement the crossover function internally are known as MDI-X ports (where “X” refers to the crossover function).

Passport 8000 switch
1	8
	1	RX+
T	2	RX-
	3	TX+
	4
R	5
	6	TX-
	7
	8
MDI-X port

8	1	8	1
	1		1
	2		2
	3		3
	4		4
	5		5
	6		6
	7		7
	8		8
	Straight-through cable

	End station
1	8
TX+	1	T
TX-	2
RX+	3
	4	R
	5
RX-	6
	7
	8
MDI port
		617EF

Figure A-1. MDI-X to MDI Cable Connections

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