RJ45 pinout

The RJ45 Pinout


The RJ 45 pinout is a result of the TIA standardization of cabling between commercial buildings.  Many telecommunications, data, audio and other industries have adopted this protocol. 

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The EIA/TIA and over 60 additional organizations contributed to this new standard. Terminated in the RJ45 connector, the 100-ohm, 8 conductor twisted pair cable known to many as Ethernet, is now ubiquitous. What is formerly a data or telecom related cable/connector is now in use worldwide to stream HD video, interface with security cameras, transmit audio, and send low voltage power, sometimes a mixture of signals and power. Many devices convert the signal at the transmit end to a different format, send the information then decode it again at the other end to gain certain advantages for the device. The RJ45 connector and standard RJ45 pinout are used in many ways in today’s technology. Other devices utilize the telecommunications standards to send data between two or more devices, such as computer Ethernet ports, which are bi-directional.  The RJ45 and its pinout have become a common sight in almost every aspect of our lives. 

Many companies spanning several industries adopted the new cabling standard terminating in an RJ45 connector leading to vastly more people familiarizing themselves with the format and the standards. Orange white/Orange, Green white/Blue, Blue white/Green, Brown white/Brown is the common color code for this connectors This code, used for RJ45 connectors is called the 568B RJ45 pinout standard and is used throughout the Telecom and AV industries today.

The reason why the RJ45 pinout is the way it is relates to crosstalk. When the conductors are paired up and twisted, they naturally resist crosstalk from signals in the other pairs.  From one end to the other, the pairs inside must be twisted at different amounts and this tolerance has to extend all the way to the ends of the cable in order to take full advantage of the phenomenon.  The RJ45 pinout is a reflection of the science behind the standard 

As the years move forward and technology avails new options, new innovations will be driven and developed which may require new formats and new standards. For now, the RJ45 connector and its familiar RJ45 pinout will be our mainstay.

Tech Addendum

As it relates to the integrity of the cable and the connectors, there are some methods you want to always practice when handling and installing twisted pair cable so the infrastructure supporting your signal path is at maximum integrity.

Bend Radius:

CAT 5-6-7 permanent installation cable that is of high quality will have solid conductors and thus cannot be kinked or too sharply bent as the solid conductors within the jacket will weaken with each successive excess bend. Always handle the cable without exerting excess force on it. If an end of a cable that was determined to be kinked or damaged, its slack should be cut to ensure a faulty cable does not get terminated.


When using standard RJ45 connectors, it is important to prep the cable then visually inspect it one final time before you apply the crimper. This way is you do not have the conductors all in a position for a 100% good connection, you can re arrange them before crimping and only crimp the cable one time. 

When using the EZ RJ45 connector, one may pull the strands out the end of the connector, pull slightly in opposite directions the connector and the strands and thus capture maximum insulation under the crimp thusly creating a more solid termination. Prior to crimping, twist all 8 conductors together slightly as to create one big scrap cut off. Crimp connector and insure all 8 wires are cut perfectly flush.  A small bit of dangling insulation is all that is needed to keep your end from locking into place so make sure the end is free of stragglers!

Jack Field
Jack Field