Cable Categories and Specifications

This appendix describes the following cable categories and specifications:

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, token ring, and other network topologies.

The EIA/TIA defines the following five categories of twisted-pair cable:

10BASE-T Standard

10BASE-T is the IEEE 802.3 standard for Ethernet signaling over unshielded twisted-pair wire at 10 Mbps.

The SuperStack II Hub 100 supports only 100 Mbps network topologies. Access to 10 Mbps functionality is possible through connections with switches, bridges, or routers that support 10/100 Mbps topologies.

Ethernet, the most widely used network protocol, uses 10BASE-T as its primary cabling scheme. Ethernet's characteristics include:

The specified networking technology for Ethernet is its MAC protocol, called Carrier Sense Multiple Access with Collision Detection (CSMA/CD). Ethernet uses CSMA/CD to prevent network failures when two devices try to access the network at the same time.

10BASE-T Specification

The 10BASE-T designation indicates a signaling speed of 10 Mbps and twisted-pair wiring. Base denotes baseband, which is a technology that transmits signals as direct-current pulses rather than as modulated signals on separate carrier frequencies.

The 10BASE-T 802.3 specification calls for a central hub with nodes wired in a star topology using unshielded twisted-pair cable. Each node has a separate cable run that must not exceed 100 meters (328 feet) from the node to the hub.

100BASE-T Standard

The 100BASE-T Fast Ethernet standard defines a network architecture based on the 10BASE-T standard that retains almost all elements of the original IEEE 802.3 Ethernet specification, while greatly increasing the network's overall throughput.

100BASE-T has the following similarities to 10BASE-T:

100BASE-T media specifications, which include 100BASE-TX, 100BASE-T4, and 100BASE-FX, allow Fast Ethernet to run on the most common Ethernet wiring, including Categories 3, 4, and 5 unshielded twisted-pair, shielded twisted-pair, and fiber-optic.

100BASE-TX Specification

100BASE-TX designates the IEEE 802.3 specification for 100 Mbps Ethernet signaling with CSMA/CD over two pairs of Category 5 UTP or STP wire. The pairs of wires used for transmitting and receiving signals are the same as those used for 10BASE-T. Therefore, the same (Category 5 UTP or better) cable used for 10BASE-T can be used for 100BASE-TX with no change to cable termination.

100BASE-T4 Specification

100BASE-T4 is the IEEE 802.3u specification for 100 Mbps Ethernet signaling over four pairs of Category 3 or better UTP cable. This physical layer standard was specifically defined to allow 100BASE-T to be deployed over the large installed base of Category 3 voice-grade UTP.

100BASE-T4 uses four-pair Category 3, 4, or 5 UTP cable for distances of up to 100 meters. Transmission requires four pairs of cable to reduce electrical emissions and meet FCC requirements. You must have appropriately wired four-pair Category 3 UTP cable available between each network device to support 100BASE-T4 transmissions.

100BASE-FX Specification

100BASE-FX is the IEEE 802.3 specification for 100 Mbps Ethernet signaling over two strands of multimode fiber-optic cable. 100BASE-FX is used for transmissions over extended distances, downlinks, and backbones, and is especially useful in any environment subject to electrical interference.

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