Networking
Category 5 Wire
The University of Findlay's College of Education

Cat 5

Category 5 wire is four-pair 100 ohm UTP (unshielded twisted pair) cable. The horizontal cabling (from the wall jack to the wire closet) may be up to 90 meters in length.

Wall Jack

Each wire is terminated into a wall jack, both in the classroom and in the wire closet. The manufacturer color-codes each connector so that installers can easily "punch-down" each colored wire in the appropriate location.

RJ45

Each patch cord has an RJ45 connector on each end. The wire diagram for the RJ45 connector is below.

RJ-45 Connectors - Patch Cords for Category 5 Wire

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Standard Patch Cord (both ends same) Cross-over Cable (only one end is crossed)

Straight-Through vs Cross-Over In general, the patch cords that you use with your Ethernet connections are "straight-through", which means that pin 1 of the plug on one end is connected to pin 1 of the plug on the other end. Voice cables are "crossed" end to end; data cables aren't.

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The only time you cross connections in 10BaseT is when you connect two Ethernet devices directly together without a hub. This can be two computers connected without a hub, or two hubs via standard ethernet ports in the hubs. Then you need a "cross-over" patch cable, which crosses the transmit and receive pairs, the orange and green pairs in normal wiring. In a cross-over cable, one end is normal, and the other end has the cross-over configuration.More Standards A good FAQ on cabling standards is at Ohio State