Nortel Networks 207344-B manual UTP Cabling, 10BASE-T/100BASE-TX MDI Ports and MDI-X Ports

Using the Centillion EtherSpeedII Switch Modules

UTP Cabling

A10BASE-T/100BASE-TX connection between two ports requires two twisted pairs. The transmit data (TD) pair carries data out from the port transmitter. The receive data (RD) pair carries data in to the port receiver.

The 10BASE-T/100BASE-TX TD and RD circuits must be connected as follows:

•Individual conductors must provide pin-to-pin continuity (TD+ to RD+, TD- to RD-, and so on) between the EtherSpeedII switch module port and the attached MDI port on a transceiver or other network interface.

•Each signal circuit must use a single twisted pair throughout the link.

•Standard Ethernet patch panels and cables provide the previous features.

10BASE-T/100BASE-TX MDI Ports and MDI-X Ports

In the 10BASE-T/100BASE-TX standard, MDI is the electrical and mechanical interface specified for the 10BASE-T/100BASE-TX transceiver or network interface card connector (for example, on the station at the end of a link).

MDI port pins 1 and 2 carry the transmit (TD) signal, and pins 3 and 6 carry the receive (RD) signal as shown in Figure B-1.

1		1
Transmit		Transmit
2		2
	Twisted pairs
3		3
Receive		Receive
6		6
MDI port network	Host module MDI-X port
interface card or	(transmit and receive
transceiver port	connections reversed)
			9729EA

Figure B-1. MDI-X Internal Crossover (RJ-45 Example)

B-2 207344-B