SMC Networks SMC8124PL2 manual Straight-Through Wiring, Cables

B Cables

Table B-1 10/100BASE-TX MDI and MDI-X Port Pinouts

Pin	MDI Signal Name	MDI-X Signal Name
1	Receive Data plus (RD+)	Transmit Data plus (TD+)
	and GND (Positive Vport)	and -48V feeding power (Negative Vport)
2	Receive Data minus (RD-) and	Transmit Data minus (TD-)
	and GND (Positive Vport)	and -48V feeding power (Negative Vport)
3	Transmit Data plus (TD+)	Receive Data plus (RD+)
	and -48V feeding power (Negative Vport)	and GND (Positive Vport)
6	Transmit Data minus (TD-)	Receive Data minus (RD-)
	and -48V feeding power (Negative Vport)	and GND (Positive Vport)
4, 5, 7, 8	not used	not used

Note: The “+” and “-” signs represent the polarity of the wires that make up each wire pair.

Straight-Through Wiring

If the twisted-pair cable is to join two ports and only one of the ports has an internal crossover (MDI-X), the two pairs of wires must be straight-through. (When auto-negotiation is enabled for any RJ-45 port on this switch, you can use either straight-through or crossover cable to connect to any device type.)

You must connect all four wire pairs as shown in the following diagram to support Gigabit Ethernet connections.

EIA/TIA 568B RJ-45 Wiring Standard 10/100BASE-TX Straight-through Cable

White/Orange Stripe

		Orange
	1	White/Green Stripe	1
End A	2	Blue	2	End B
	3		3
	4		4
	5	White/Blue Stripe	5
	6	Green	6
	7		7
	8	White/Brown Stripe	8

Brown

Figure B-2 Straight-through Wiring

B-2