Category 5 and 5E Cable Colour Sequence

Category 5 and 5E cabling utilises a standard conductor colour coding system. Each pair of conductors consists of a white conductor and a coloured conductor. Each white conductor is usually marked with a coloured stripe or band to prevent incorrect pairing.

Two different pair sequences are used for terminating pairs in a Cat5 or Cat5e cabling system. Each pair consists of 2 conductors known as the Tip and Ring. The tip (or L+) conductor is always white the Ring (L-) conductor is coloured. Each pair of conductors is assigned a pair of pins in the modular jack according to one of the following standard sequences.

Straight through and crossover cables

Modular Cables

Flat modular cables can be wired in either straight trough or crossover configuration Crossover wiring is most commonly used for connection of equipment such as telephones, modems, faxes and terminals to a modular wall outlet. However voice applications will usually tolerate either configuration. Data equipment may use either straight through or crossover depending on the equipment's specifications. Accessories such as couplers and double adapters are available in straight trough or as crossovers.

Flat Modular Cable Wiring Configuration

Checking Flat Modular Cable Wiring Polarity

Hold both ends of the modular cable with the plugs alongside each other. Ensure that the contacts of both plugs are facing you and the cable from each plug is leading down. The contacts are numbered from left to right with the plugs in this orientation. Compare the colour sequence from the left to right. If the colours appear in the same sequence on both plugs, the lead is wired straight through. If the sequence is reversed on the second plug, then the lead is wired crossover.

Category 5 and 5e Patch Leads

The majority of patch leads used for connections between the sockets on a patch panel, from a PC or terminal to a wall outlet are wired straight through in T568A to T568A configuration. Crossover leads are used to daisy chain switches, hubs or for direct connection of two computer network interface cards. Crossover wiring is T568A to T568B with the wiring of the green and orange pairs transposed.

Category 5, 5e and 6 Modular Wiring Configurations