APPENDIX C Cables and Pinouts

10/100BASE-TX Pin Assignments

10/100BASE-TX PIN ASSIGNMENTS

Use unshielded twisted-pair (UTP) or shielded twisted-pair (STP) cable for RJ-45 connections: 100-ohm Category 3 or better cable for 10 Mbps connections. Also be sure that the length of any twisted-pair connection does not exceed 100 meters (328 feet).

The RJ-45 port on the access point supports automatic MDI/MDI-X operation, so you can use straight-through or crossover cables for all network connections to PCs, switches, or hubs. In straight-through cable, pins 1, 2, 3, and 6, at one end of the cable, are connected straight through to pins 1, 2, 3, and 6 at the other end of the cable.

Table 5: 10/100BASE-TX MDI and MDI-X Port Pinouts

PIN

MDI Signal Namea

MDI-X Signal Name

 

 

 

1

Transmit Data plus (TD+)

Receive Data plus (RD+)

2

Transmit Data minus (TD-)

Receive Data minus (RD-)

3

Receive Data plus (RD+)

Transmit Data plus (TD+)

6

Receive Data minus (RD-)

Transmit Data minus (TD-)

4, 5, 7, 8

Not used

Not used

a.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.

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SMC Networks SMCWBR14S-N4 manual 10/100BASE-TX PIN Assignments, STRAIGHT-THROUGH Wiring