Copyright Goodheart-Willcox Co., Inc. 77 Chapter 2 Network Media—Copper-Core Cable When a token ring network incorporates a MAU, twisted-pair cable is used. Th e twisted-pair cable attaches to an RJ-45 connector. Token ring only uses two pairs for communication and has one standard, 568A, as described in Figure 2-34. Wiring Faults When installing twisted-pair cabling, the pairs of conductors inside the cable jacket must be connected correctly at both ends or the network will not be able to com- municate. Th e proper connection of individual conductors to pins is outlined in TIA standards T568A and T568B. Th e proper connection sequence must be maintained throughout the installation, from the network card to the server room. Incorrect wir- ing can result in shorts, opens, reversed pairs, crossed pairs, and split pairs. Short A short occurs in cabling when two conductors are improperly connected, resulting in a shorter circuit path. Look at the lamp circuit in Figure 2-35. Th e lamp circuit is connected with the splice point left open for viewing. Most short circuits and open circuits occur at splice points and connection points. In Figure 2-35A, the circuit is correctly wired. When the switch is closed, electrical energy fl ows through the lamp, and the bulb in the lamp is lit. In Figure 2-35B, the wires are touching at the splice point. Th e same can be applied to networking media. When the switch is closed, the electrical energy cannot reach the lamp because the electrical energy routes through the shortest path, the splice point. When a short occurs in a network cable, data takes a shorter route and does not reach its destination. 5.3 NET 1 2 Token Ring (802.5) uses cable pairs 1 and 2 for communication 4 3 6 5 568A Pair 1 Pair 2 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Figure 2-34 The 802.5 standard specifies that only the 568A connection standard be used. Note that pairs 1 and 2 are used for communication. Goodheart-Willcox Publisher