Ethernet cables are used to connect devices in local area networks (LANs). They enable fast and reliable data transmission between computers, routers, switches and other network devices. The cables contain 4 pairs of wires that are color coded to help identify them. Understanding the color coding enables proper cable installation and troubleshooting of connectivity issues.
Ethernet Cable Types
There are two main types of ethernet cables:
- Cat 5 – Category 5 ethernet cable, also known as Cat 5e. It can transmit data up to 1 Gigabit per second (Gbps). This is the most common type of ethernet cable used in home and office networks.
- Cat 6 – Category 6 ethernet cable. It can transmit data up to 10 Gbps, making it ideal for high speed networks. Cat 6 cable has more stringent specifications for reducing crosstalk and system noise.
Within these types, there are ethernet cables made with solid conductor wiring and others with stranded conductor wiring. Stranded wiring is more flexible while solid wiring is lower cost.
Ethernet Cable Pinout
All ethernet cables have 8 pins or wires that are arranged in 4 paired sets. Each pair serves a specific purpose:
- Orange and Green – Transmit data
- Blue and Blue/White – Receive data
- Green/White and Orange/White – Transmit data
- Brown and Brown/White – Receive data
Thisspecific order of wire pairs and colors follows the industry standard TIA/EIA-568B pinout. The same pinout is used for both ends of an ethernet cable so that the transmit pins at one end are connected to the receive pins at the other end.
Color Coding
Ethernet cable color coding enables distinguishing the different pairs of wires inside the cable jacket. Here are the wire color codes:
| Position | Color |
|---|---|
| Pair 1 | Solid Orange and Green/White |
| Pair 2 | Solid Blue and Blue/White |
| Pair 3 | Solid Green and Orange/White |
| Pair 4 | Solid Brown and Brown/White |
A mnemonic to remember the positions is “Orange Green, Blue, Green/White Orange/White, Brown Brown”. The solid colors represent the primary wires and the striped colors are the secondary wires.
This coloring allows easy identification of the different twisted pairs within the cable. Matching up wire colors is crucial when terminating ethernet cables onto jacks or patch panels. The color coding enables technicians to quickly verify connections during installation and troubleshooting.
Wiring Standards
There are two main standards that define ethernet wiring color codes – TIA/EIA 568A and TIA/EIA 568B. The TIA stands for Telecommunications Industry Association while EIA refers to Electronic Industries Alliance.
The two standards swap the positions of the orange/green pair and green/orange pair as follows:
- TIA/EIA 568A – Green/White, Green, Orange/White, Blue, Blue/White, Orange, Brown/White, Brown
- TIA/EIA 568B – Orange/White, Orange, Green/White, Blue, Blue/White, Green, Brown/White, Brown
Most modern networks follow the TIA/EIA 568B standard. When connecting two ethernet devices, the cables at both ends must follow the same wiring convention for the network to work.
Crossover vs Straight-Through Cables
There are two main types of ethernet cables based on the internal wiring:
- Straight-through – The wires are arranged in same order at both ends following TIA/EIA 568A or 568B. Used for connecting different types of devices like switch to computer.
- Crossover – The transmit and receive wire pairs are crossed over so one end follows 568A while the other end follows 568B. Used for connecting same types of devices like switch to switch or computer to computer.
The crossover design enables transmitting on one end to the receiving pins on the opposite end. Modern ethernet adapters can automatically adjust for straight through or crossover cables.
Connector Types
Ethernet cables use various types of connectors or jacks to plug into network devices:
- RJ45 – The standard 8P8C modular connector used on most ethernet cables. It has 8 pins to connect the 4 twisted pairs.
- RJ11 – A smaller 6P2C modular connector sometimes used for telephone and DSL internet connections.
- BNC – The Bayonet Neill–Concelman connector uses a twist lock and rotation to secure the connection.
- AUI – The Attachment Unit Interface with a 15 pin connection typically used on early Ethernet networks.
The RJ45 connector is the most common for modern LAN networks. Ensure the correct connector is used when purchasing replacement ethernet cables.
Cat 5 Cable Wiring
Category 5 or Cat 5 is the most popular type of ethernet cable used in both home and office networks. These older cables can transmit network data up to 100 Mbps based on the Fast Ethernet standard.
Cat 5 cable contains four twisted wire pairs inside that are color coded based on the TIA/EIA 568B wiring standard as follows:
- Orange/White
- Orange
- Green/White
- Blue
- Blue/White
- Green
- Brown/White
- Brown
This order ensures the cable will work for either crossover or straight through connections. The wires are untwisted only at the ends when installing RJ45 connectors. Cat 5 cable is still usable for modern Ethernet networks, however slower speeds may be achieved compared to Cat 5e or Cat 6 cables when using older Cat 5.
Cat 5e Cable Wiring
Category 5e or Cat 5e is an enhanced version of Cat 5 ethernet cable. It provides improved data speeds and crosstalk performance compared to older Cat 5 cable.
The internal twisted pair color coding is the same as Cat 5 cable following the TIA/EIA 568B standard:
- Orange/White
- Orange
- Green/White
- Blue
- Blue/White
- Green
- Brown/White
- Brown
Cat 5e cables can transmit network data up to 1000 Mbps or 1 Gbps. This makes it ideal for use with modern Gigabit Ethernet networks. Cat 5e also reduces crosstalk that can interfere with signal quality and performance.
Cat 6 Cable Wiring
Category 6 or Cat 6 ethernet cable provides faster speed and better noise resistance than Cat 5 and Cat 5e. It can transmit data up to 10 Gbps and is used for 10GBase-T networks.
The Cat 6 internal wiring follows the ANSI/TIA-568-C.2 standard which is a revised version of TIA/EIA 568B. Here are the color codes:
- Green/White
- Green
- Orange/White
- Blue
- Blue/White
- Orange
- Brown/White
- Brown
Cat 6 cables have more stringent sheathing and wire twisting specifications to minimize interference. The wires must be terminated with GG45 connectors designed for higher frequency transmission.
When installing Cat 6 patch cables, care must be taken to avoid kinking or excess bending that could compromise performance. Proper Cat 6 connectors that maintain cable twisting are also required.
Conclusion
Understanding ethernet cable color coding helps ensure proper network installations. The eight wires inside ethernet cables are arranged in four color coded twisted pairs that follow wiring standards like TIA/EIA 568B.
Matching up the correct wire colors is needed for ethernet cables to work properly between devices. The two main cable types are straight-through and crossover. Common connectors used are the RJ45 plug and jack.
Newer Cat 5e and Cat 6 cables improve upon older Cat 5 for modern high speed networks. Checking the ethernet cable colors and connectors helps with setting up a new wired network or troubleshooting connectivity issues.
