You’ve run the cable, wired the keystone and punched down the patch panel and its not working. Our Keystone Jack Tester and Locator helps you create consistent and reliable wiring connections.

While, WiFi is convenient and may be enough for some, I include myself in the community that enjoys the higher speeds, reliability and security of wired networks. I do utilize WiFi as well, but this post is about some of the challenges that we have all experienced when installing our wired Ethernet networks. Below introduces the wiring challenges and is followed by the design for a device that helps us installers confirm/diagnose wiring.

At the highest level, there are typically 3 challenges the installer faces:

  1. Connections at the Wall-plate and the Patch Panel:
    • Keystone jack – great when correctly wired the first time, but if not working creates a challenge to determine if problem is with jack or other components
      1. Keystone jacks are a very common sources of wiring errors due to tight spaces.
    • Patch Panel – Generally fewer errors occur here due to punch down coloring and pairs (unlike t568 cross paired wiring on patch cables)
      1. However, punch down tool upside down can trim wire on wrong side, or just missing the right slot with the wire does occur occasionally.
  2. Identification of which wall plate is connected to which jack on patch panel
    • Industry best practice is to simply connect inbound wires to patch panel and then identify the panel port used to label the wall plates. So location on panel is needed to correctly label wall plates
  3. Wiring validation

Currently there does not exist a single product that can help installers with all 3 challenges.  The market currently has commercial products for challenge 3, and niche products for challenge 2, however I have had a difficult time finding tools for challenge 1.

I have the Sperry tool for the end to end validation, however when a we mess up the wiring on a cable run, we have to spend time with challenge 1 & 2 to be able to fix the issue. So I started to think we should have a tool for challenges 1 & 2 and then likely challenge 3 would become almost unnecessary. So below are the circuits I came up with.

Below are 2 circuits, one to test the keystone jack at the wall-plate and the second for locating that run at the patch panel. Ideally both can reside within the a single handheld device… so lets take a closer look at the 2 circuits.

Design – Challenge 1 – Keystone Wiring Validation

Keystone jacks have 8 wire connections, one for each wire in a typical Ethernet cable (and supports both TIA 568A and B).

As part of the wiring process each cable contains 4 pairs which are fed into the keystone jack. Each individual wire is bent at 90 degrees and placed across a pair of retaining clips (and typically a few extra inches of each wire extends from the side of the keystone jack used to help get wire placed into retaining clips)

Once all 8 wires are positioned, the “lid” id pressed down onto the jack, piercing the 8 wires, in the retaining clips, making connections to the plug portion of the keystone jack.  The two common errors are:

  • One or more wires move out of alignment with the retaining clips so not aligned with corresponding lids piercing connector.  So when lid pressed down on jack, that wire connection is not made.
  • Solid and striped wires are reversed…

Consider the following circuit visual of a device which can be used to confirm continuity for each of the 8 wires at the jack.

** PRECAUTION ***  Verify jack continuity either before patch panel connections made, or be sure to keep patch panel port empty ***

The Procedures for testing the Keystone Jack is as follows:

Test Device is a single Keystone jack.

  1. Each pigtail (numbered 1 – 8) is the extra few inches of each wire and each should be stripped to allow the continuity test.
  2. Test Lead is to be connected to each pigtail in succession:
    • Start with wire position (pigtail) 1.
    • When connected to each pigtail, the corresponding LED (Pigtail #5 illustrated) on the tester will light confirming wire connectivity to keystone jack pin has been made.
    • Repeat with the subsequent wire position
  3. If there are any continuity test that fail (corresponding LED does not light up), then it should be clear where the error has occurred.

Design – Challenge 2 – Keystone Identification of Patch Panel Port

When wiring a building patch panel, industry best practice is to simply wire the cables up as they are available without any pre planning to number cable runs.  Once Keystone jack wiring validated, and cables punched into patch panel, the second step is to simply identify each keystone jack and label the wall-plate with the patch panel port for the respective jack. This is an enormous time saver.

Consider this circuit visual for a device which can be used to identify wall plate keystone jacks at the patch panel.

The Procedures for identifying the Keystone Jack is as follows:

Test Device is the Keystone jack.

  • Plug the Keystone locator into the keystone jack being located.
  • At the patch panel, plug in Identifier RJ45 plugs into candidate patch panel ports ( easiest to simply fill the patch panel with these to shorten location exercise)..
    • The locator is sending a DC signal to the patch panel port.
    • The identifier RJ45 plug LED plugged into the corresponding patch panel port will light. 
    • Create label for wall-plate keystone jack using the patch port number to be affixed to the wall-plate.
      • Also document this in the network diagram

Initial prototypes of a single device with these two circuits includes the following parts:

  • 1 x Carlon old work box (blue / shallow) (Home Depot (cheaper) or Amazon Link)
  • 1 x 2 gang Keystone wall plate (Amazon Link)
  • 2 x Keystone jacks (Amazon Link)
  • 1 9v Battery (could choose differently but didn’t want to guess with long cable runs)
  • 1 x 4mm Banana plug for test lead connection to device (Amazon Link)
  • 1 test lead (4mm banana on one end and clip or alligator clip on other)
  • 1 x on off switch (Amazon Link)
  • 8 green LEDs (I chose 5mm) for continuity indicators (Amazon Link)
  • 1 red LED (for power) (Amazon Link)
  • Sets of RJ45 jacks, each with a single 3mm LED from pin 5 to pin 4. (Etsy Link)
  • I created a small Printed Circuit Board to hold the LEDs and resistors (Etsy Link)

Optionally, I used some rubber feet to have wall-plate standoff the Carlon box for fitment since my wall plate had funny screw recesses.

The small circuit board to hold all the resisters and LED and will likely get an upgraded version 2 to simplify the soldering connections and wire connections in the box.

I have created a <YouTube video> to show how I constructed the prototype and the device is available from our sister Etsy store as a tested device, component parts or simply the small circuit board.



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