Understanding RJ45 Connectors & Selecting The Right Type

  • Last modified: July 14, 2023
rj45 guide

RJ45 Connectors, connector, 8P8C …… all these terms are used interchangeably. All these terms refer to the piece attached to the end of an Ethernet cable that plugs into your router, computer, and television. While all these terms are used interchangeably, it’s important to mention that the correct term for this wonderful device is 8P8C RJ45 Ethernet connector – here, 8P8C refers to eight position/eight conductor whereas RJ stands for registered jack; 45 refers to the listing number. 

Now a question will be popping up in your mind: what does this amazing little device do, and how does it work? Just stay with us as we unravel this mystery for you once and for all. 

To put it simply, RJ45 Connector, 8P8C, RJ45 Plug is a piece of plastic accompanied by as many as eight golden contacts inside. To your surprise, an RJ45 plug is not a “Cat” type thing. Here the question arises: does one size fit all? Let’s answer it. 

The answer is a big NO! When it comes to the outside, the dimensions are the same (because of the requirement that an RJ45 plug has to be of this standard dimension so that it can fit into any standard RJ45 port). However, when it comes to inside structure, here is where you can trace the major differences. Therefore, it becomes indispensable to have ample knowledge so that you can make informed decisions when buying these connectors. 

You may know that there exist some loose standards around how to manufacture various types of ethernet cables. Ethernet cables differ in copper conductor AWG aka gauge thickness, and insulated conductor thickness. It means you should know what will fit inside the RJ45 connector and how big a specific ethernet cable is. Technically speaking, you should know the Category of ethernet cable you are working with. 

There’s another difference that you should know, i-e 2-prong and 3-prong connectors. 2-prong connectors are designed for stranded Ethernet cables, whereas 3-prong connectors are designed for solid Ethernet cables. The biggest difference between a solid cable and a stranded cable is that of performance. Higher gauge/thinner conductors have more insertion loss than lower gauge/thicker conductors; also, when it comes to attenuation, stranded cables exhibit 30% to 50% more attenuation than solid copper conductors. 

Another important factor to take into consideration is that not all plugs are plastic from the outside. To put it simply, your RJ45 connector is an engineering marvel. In case you are wondering, there are no little chips inside the connector. 

Selecting The Right Connector

Selecting the right connector thoroughly depends on the construction and type of cable that needs to be run – as a matter of fact, it is all about fitment. 

If your Ethernet cable is shielded, then you will need a shielded RJ45 plug. Likewise, if you are using an unshielded Ethernet cable, then you will use an unshielded connector. If you plan to use a shielded connector with an unshielded cable, let us reveal that it is of no use – a fitment issue may arise. Technically speaking, the shielded RJ45 connectors are up-size and are unable to make proper connections with thinner conductors of unshielded Ethernet cables. 

Specification Cat5e Cat6 Cat6a
Cable Jacket Plenum, Riser & PVC Plenum, Riser & PVC Plenum & Riser
Wire Gauge 24-AWG 23-AWG 23-AWG Highly Twisted
Frequencies 350 MHZ 550 MHZ 750 MHZ
Installation Temp 0°C to 60°C 0°C to 60°C 0°C to 60°C
Pairs 4 Twisted Pairs 4 Twisted Pairs 4 Twisted Pairs
Package Easy Pull Box Easy Pull Box Wood Spool
Colors Black, Blue, White, Red, Green, Yellow Black, Blue, White, Red, Green, Yellow Black, Blue, White, Red, Green, Yellow
Written By:

Ryan, a seasoned networking professional with over a decade of experience. He is passionate about all-things tech and avidly reads IT journals.

Subscribe to Work Life

Get stories like this in your inbox

Leave a Reply