3Com 3CR990 manual Connection Criteria, Network Cable

66APPENDIX A: SPECIFICATIONS

Network		The following table provides network connection criteria for the 3CR990 NICs.
Connection Criteria
			Network Cable		Maximum
NIC	Cable		Connector	Transceiver	Network Segment	Speed	Media Type
3CR990-TX-9X Category 3, 4, or 5			RJ-45	On-board	328 ft/100 m	10/100	10BASE-T
	unshielded twisted-pair					Mbps	100BASE-TX
Network Cable		This section provides information about various network cable standards and
		descriptions of those standards for EtherLink 10/100 PCI NICs.

Cabling Requirements The cable type, quality, distance, and connectors must comply with the Electronic Industries Association/Telecommunications Industries Association (EIA/TIA) 568 Commercial Building Wiring Standard and the Technical Services Bulletin TSB38 standards.

Twisted-Pair Cable Twisted-pair cable consists of copper wires surrounded by an insulator. Two wires are twisted together (the twisting prevents interference problems) to form a pair, and the pair forms a circuit that can transmit data. A cable is a bundle of one or more twisted pairs surrounded by an insulator.

Unshielded twisted pair (UTP) is the most commonly used type of twisted-pair cable. Shielded twisted pair (STP) provides protection against crosstalk. Twisted-pair cable is now commonly used in Ethernet, Fast Ethernet, and other network topologies.

Unshielded Twisted-PairThe following table shows the five categories of unshielded twisted-pair cable as Cable Categories defined by the EIA/TIA.

Category Use

1Traditional telephone cable.

2Data transmissions up to 4 MHz.

3Voice and data transmission up to 25 MHz. The cable typically has four pairs of wires. Category 3 is the most common type of installed cable found in older corporate wiring schemes.

4Voice and data transmission up to 33 MHz. The cable normally has four pairs of wire. This grade of UTP is not common.

5Voice and data transmission up to 125 MHz. The cable normally has four pairs of copper wire and three twists per foot. Category 5 UTP is the most popular cable used in new installations.

10BASE-T Description 10BASE-T is the Institute of Electrical and Electronics Engineers (IEEE) 802.3 standard for Ethernet signaling over unshielded twisted-pair wire at 10Mbps.

Ethernet, as the most widely used network protocol, uses 10BASE-T as its primary cabling scheme. Ethernet characteristics include:

■A data rate of 10 Mbps

■A broadcast architecture

■A specific media-access control (MAC) scheme