Selecting the Correct RJ45 Connector Before Buying

Author: Campus Component

If you’re a beginner to network installation, I guess you will be confused about terms such as RJ45, 8P8C, modular plug, and so on. All of these terms are related to devices that are attached to the end of Ethernet cables. We’re talking about all things about RJ45 connectors here to let you have a better understanding of them.

The modular connector system was developed by AT&T in the 1960’s and 1970’s to take the place of bulky phone connectors and their labor-intensive installation. This new connector system offered simple, quick, and convenient setup that could be customized on-site by a technician or installed by the user in the home. The line has expanded over the years to include data communication mainstays, like the RJ45, which was developed for computer networking. In fact, RJ45 connectors are commonly referred to as Ethernet Connectors.

Do you know what "RJ45" means in the RJ45 connector? Let me explain it. "RJ" is the abbreviation of "registered jack", which originally means a standardized telecoms network interface for voice and data devices connection. It was first defined in the USCO (Universal Service Ordering Code) of Bell System and in the 1970s, it was licensed by FCC (Federal Communications Commission) to maintain the compatibility between customer devices and telephone service provider equipment. "45" means the listing number of networking interface standards.

What you need to know about the Ethernet cable is this:

  • The Ethernet cable's outer diameter is measured in OD (the overall thickness). Typically, this is stated in millimeters (mm).
  • Similar to conductor diameter, conductor insulation diameter is frequently given in millimeters and consists of the conductor wire itself plus the thickness of the insulation.
  • whether the cable has stranded or solid conductors
  • AWG copper gauge

To choose the best RJ45 connector, you must understand:

  • The maximum cable jacket OD the plug can take
  • The range of conductor insulation diameters that the plug can accommodate
  • whether the plug has two or three prongs. Both stranded and solid copper conductors can be used with three-prong plugs. Plugs with two prongs only operate with stranded copper.
  • AWG copper gauge

Observe the potential tolerances (-/+) for the Ethernet cable's conductor insulation diameter. Choose an RJ45 plug such that the nominal diameter of the insulated conductors in the cable you intend to use matches the middle of the plug's fitting range. This will aid in taking into consideration any variations in manufacturing tolerance that can and do happen.

To better understand what we want, let's look at the specification sheets that true CABLE publishes. Assuming you're looking for the right RJ45 for our Cat6 Riser Unshielded Ethernet cable in bulk:

  • The diameter of the conductor insulation is 0.96mm.
  • The overall cable thickness, or cable jacket, is 5.90mm.
  • 23AWG solid copper conductors are used in the cable.

With those specifications in hand, we would then need to select the true cable Cat6/6A Pass-Through RJ45 connector (if you wish to use pass through).

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