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3.2 10BASE5 Components

AUI Cable (Transceiver Cable)

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An AUI cable can be used to provide the connection between an external MAU and the Ethernet interface. The MAU is equipped with a male 15-pin connector with locking posts, and the Ethernet interface (DTE) is equipped with a female 15-pin connector that is typically provided with a sliding latch.*1

The AUI cable, in turn, has a female 15-pin connector on one end that is equipped with a sliding latch; this is the end that is attached to the MAU. The other end of the AUI cable has a male 15-pin connector that is typically equipped with locking posts; this is the end that is attached to the Ethernet interface. Some 15-pin connectors on Ethernet interfaces are equipped with screw posts instead of the sliding latch fastener described in the standard, requiring a special AUI cable with locking screws on one end instead of sliding latch posts.

A transceiver cable is built like an electrical extension cord; there's a plug (male connector) on one end, and a socket (female connector) on the other end. If you needed to, you could connect several AUI cables together to reach between an interface and a MAU. This is not recommended, however, since the sliding latch connectors may not hold the cable ends together very well.

The AUI cable carries three data signals between the Ethernet interface and MAU: transmit data (from the Ethernet interface to the network), receive data (from the network to the interface), and a collision presence signal (from the network to the interface). Each signal is sent over a pair of wires. Another pair of wires are used to carry 12 volt DC power from the Ethernet interface to the MAU.

The standard AUI cable is relatively thick (approx. 1cm or 0.4 inch diameter), and may be up to 50 meters (164 feet) long. "Office grade" AUI cables are available that are thinner and more flexible. The thinner wires used in office grade AUI cables also have higher signal loss than the wires in standard AUI cables, which limits the length of office grade cables. One vendor of office grade cables rates them as having four times the amount of signal attenuation as standard cables, and only sells them in two and five meter lengths. The maximum allowable length between a station and a MAU for these office grade AUI cables is 12.5 meters (41 feet).

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Quick Reference Guide to 10BASE5 Thick Ethernet - 04 SEP 95

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