3Com 3CR990-TX-97, 3CR990-TX-95, 3CR990SVR97 RJ-45 Connector Pin Assignments, 100BASE-TX Operation

156APPENDIX B: SPECIFICATIONS AND CABLING REQUIREMENTS

100BASE-TX Operation

100BASE-TX is the IEEE 802.3u standard for Fast Ethernet signaling over Category 5 UTP or STP wire at 100 Mbps.

Based on an extension to the IEEE 802.3 Ethernet specification, Fast Ethernet characteristics include:

■A data rate of 100 Mbps.

■A broadcast architecture.

■A specific media-access control (MAC) scheme.

A wiring topology using 100BASE-TX specifies a wiring hub, cable arranged in a star configuration, and Category 5 UTP or STP wiring. Each node has a separate cable run that must not exceed 100 meters (328 ft) from the node to the hub.

RJ-45 Connector Pin Assignments

The following illustration shows the RJ-45 connector pin assignments for the EtherLink PCI NICs.

TX
DATA
ACT
10	L
100	N
	K

1TD+

2TD_

3RD+

6RD_

1 2 3 4 5 6 7 8