3Com 3CR990 manual Assignments, 1 TD+ 2 TD 3 RD+ 6 RD, 1 2 3 4 5 6 7

Network Cable 67

The 10BASE-T name indicates a signaling speed of 10 Mbps and twisted-pair wiring. Base stands for baseband, which denotes a technique for transmitting signals as direct-current pulses rather than modulating them onto separate carrier frequencies.

A wiring topology using 10BASE-T specifies a wiring hub, cable arranged in a star configuration, and unshielded twisted-pair cable. Each node has a separate cable run that must not exceed 328 ft. (100 meters) from the node to the hub.

100BASE-TX Description 100BASE-TX is the IEEE 802.3u standard for Fast Ethernet signaling over

Category 5 UTP or STP wire at 100Mbps.

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 328 ft. (100 meters) from the node to the hub.

RJ-45 Connector Pin	The following figure shows the pin layout for the RJ-45 connector socket on the
Assignments	NIC backplate.

TX DATA

ACT
10	L
100	N
	K

1TD+

2TD_

3RD+

6RD_

1 2 3 4 5 6 7 8