Ethernet cables are used to connect devices in local area networks (LANs). There are a few different categories of ethernet cables, with different speed and cable quality ratings. However, all ethernet cables use color coding to indicate which wires should be connected. Understanding the color order for ethernet cables is important for properly installing and crimping ethernet cables.
Twisted Pair Cabling
The most common type of ethernet cabling is twisted pair cabling. This uses color coded pairs of wires that are twisted together to help reduce crosstalk interference. There are two main categories of twisted pair ethernet cable:
Category 5
Category 5 cable, also known as Cat 5, was commonly used in old ethernet networks and could support speeds up to 100 Mbps. Category 5 has four twisted pairs usually distinguished by the colors blue, orange, green, and brown. Each pair is twisted with a different number of twists per inch to keep them separated and reduce noise.
Category 6
Category 6 cable, or Cat 6, is an upgraded version of Cat 5 and can support gigabit ethernet speeds up to 1000 Mbps. The color order for Cat 6 is very similar to Cat 5, with four twisted pairs using the colors blue, orange, green, and brown. However, Category 6 uses more twists per inch and higher quality copper than Cat 5 cable.
T568A vs T568B Wiring
There are two common standards used for wiring the colored pairs in ethernet cable, known as T568A and T568B. Both standards specify the same colors but differ in which pairs they connect.
T568A
The T568A standard uses the following color order:
| White/Green | Green |
| Green | White/Green |
| White/Orange | Blue |
| Blue | White/Blue |
| White/Brown | Orange |
| Orange | White/Brown |
T568B
The T568B standard uses this color order:
| White/Orange | Orange |
| Orange | White/Orange |
| White/Green | Green |
| Green | White/Green |
| White/Brown | Blue |
| Blue | White/Blue |
Straight Through vs Crossover Cable
Ethernet cables are either wired as straight through or as crossover cables:
Straight Through Cable
A straight through cable follows the same color order on both ends. It is used to connect devices of different types, like connecting a computer to a switch or router. Straight through cables should be wired to the T568B standard.
Crossover Cable
A crossover cable has the transmit and receive pairs crossed, so that one end follows T568A and the other end follows T568B. Crossover cables are used to connect similar devices like switch-to-switch or computer-to-computer.
How to Remember the Color Order
Remembering the specific color order for ethernet cables can be challenging. Here are some tips:
– Use mnemonics like “White Orange Green Brown Blue” for the colors in T568B
– Visualize connecting colored pairs between two devices
– Reference a wiring diagram like the ones above
– Use the same standard, like T568B, if you know you need a straight through cable
Crimping Ethernet Cables
Once you’ve wired the ethernet cable to the correct color order, it needs to be properly terminated. This is done by crimping connectors onto each end.
To crimp ethernet cables:
Cut the cable
Cut the ethernet cable to the desired length using wire cutters. Leave at least six inches of extra length for mistakes.
Strip the outer jacket
Strip off about 1.5 inches of the outer plastic jacket from the cut end using a cable stripping tool. Be careful not to nick the wires underneath.
Untwist and arrange the wires
Untwist the wire pairs and neatly align them according to the desired T568A or T568B order. Trim the ends so they are even.
Insert into connector
Hold the arranged wires firmly and insert them fully into the RJ45 connector, making sure the colors align with the connector guides.
Crimp the connector
Using a crimping tool, securely crimp the connector at the base to hold the wires in place.
Test connector
Test that no wires pull out of the connector and that there is metal visible on all eight contact points inside the connector.
Testing Ethernet Cables
After crimping RJ45 connectors on the ethernet cable, it should be tested to verify it is working properly:
– Use a cable tester that shows connectivity and indicates faults
– Test cable at short lengths before running long lengths
– Verify end-to-end connectivity between devices
– Re-terminate any faulty connectors and retest
– Ensure speeds match category rating of the cable
Conclusion
Ethernet cables use specific color orders and wiring standards to maintain compatibility between devices. The two main standards are T568A and T568B which differ only in the pairing of the colored wires. Straight through cables should follow T568B, while crossover cables connect one end T568A and the other T568B. Following the correct color order, properly crimping connectors, and testing cables is key to a properly functioning ethernet network. Knowing the details of the color codes and wiring standards allows for reliable ethernet cable installation.
