SMC Networks SMC7800A/VCP B-2, 10BASE-T/100BASE-TX Pin Assignments

ABLES

B-210BASE-T/100BASE-TX Pin Assignments

Use unshielded twisted-pair (UTP) or shielded twisted-pair (STP) cable for

RJ-45 connections: 100-ohm Category 3, 4 or 5 cable for 10 Mbps

connections, or 100-ohm Category 5 cable for 100 Mbps connections.

Also be sure that the length of any twisted-pair connection does not

exceed 100 meters (328 feet).

The RJ-45 ports on the CPE support automatic MDI/MDI -X operation,

so you can use straight-through cables for all network connections to PCs

or gateways. In s traight-th rough 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. When using the RJ-45 port on this CPE, you can use either

straight-through or crossover cable.

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

Pin MDI Signal Name 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

Note: The “+” and “-” signs represen t the polarity of the wires that

make up each wire pair.