Ethernet LAN cables can come in two different types – Crossover or Straight through. Most modern communications equipment can auto sense which type you are using, but some still need the correct cable pinout. The following are the pinouts for the RJ45 connectors so you can check which one you have or make up your own. It doesn’t matter if you are making up some Cat5e, Cat6 and Cat7 cables the pinout is always the same for Ethernet cables.
Straight Through LAN Cable Pinout
Straight through LAN cables are the most common and the pinout is the same if they are Cat5e, Cat6 or Cat 7. The different types of cables (category or cat) offer increasingly faster transmit and receive speeds, this is achieved by increasing the wire twists, better shielding, drain wire and increased wire diameter.
There are two different pinout standards used worldwide and depending on your location will determine which one you should use. An easy way to remember the two different RJ45 connector pinouts is T568A is used in America and Asia and the T568B is used in Britain(UK) and Europe. The different pinouts will still work if you mix them up.
- T-568A – Most commonly used in the USA and Asia – Just think A for America
- T-568B – Britain (UK) and Europe
RJ45 Pinout for a LAN Cable
- Pin 1 → White and Green (Transmit +) wire
- Pin 2 → Green (Transmit -) wire
- Pin 3 → White and Orange (Receive +) wire
- Pin 4 → Blue wire
- Pin 5 → White and Blue wire
- Pin 6 → Orange (Receive -) wire
- Pin 7 → White and Brown wire
- Pin 8 → Brown wire
Remember that Pin 1 is on the left hand side of the RJ45 connector with the clip at the rear.
Crossover Ethernet Cable
Crossover Ethernet cables are used to connect two devices of the same type together. Like you want to connect two routers or two PCs. Most modern IT equipment can auto detect that a crossover needs to be made and makes changes to the signal, this is called MDI-X. A crossover LAN cable will connect the receive at one end to the transmit at the other. Care must be taken to clearly identify a crossover cable so it is not used by mistake as this may cause network outages. These cables are sometimes made with cable that has a red outer sheath.
RJ45 Pinout for a Crossover LAN Cable
- Pin 1 ← White and Green wire → Pin 3
- Pin 2 ← Green wire → Pin 6
- Pin 3 ← White and Orange wire → Pin 1
- Pin 4 ← Blue wire → Pin 4
- Pin 5 ← White and blue wire → Pin 5
- Pin 6 ← Orange wire → Pin 2
- Pin 7 ← White and Brown wire → Pin 7
- Pin 8 ← Brown wire → Pin 8
How to Crimp a RJ45 LAN Connector
Follow these steps to make sure you make the perfectly crimped RJ45 connector:
- Trim the outer sheath back about 10mm to expose the inner conductors.
- Trim off any nylon strands or wire guides
- Straighten the wires
- Sort them out to the correct colour codes for the pinout
- Snip the wires so they are all the same length
- Push the wires in to the connector
- Make sure the outer sheath in inside the RJ45 crimp
- Crimp the connector
- Test the Ethernet cable
Ethernet Cable Lengths
The recommended maximum length for any structured cabling is 100m. This includes 5m of patch cables at either end of the cable run so the actual distance for the fixed cabling is 90m. Anything over this distance then you will start to introduce interference and losses on the cable and this will be seen as errors, dropped traffic packets and reduced throughput.
Structured Cabling = 90m
LAN Patch Cables = 2 x 5m
It’s good installation practice to keep the cable runs as short as possible and not to leave unnecessary excessive service loops of cable.