VDV Works Virtual Hands-On Training


Cat 3 and Cat 5/5E/6 UTP Termination

Cat 3 Jacks


Step 1 NEXT BACK  Terminating Cat 3 Jacks
You will need:
Cat 3 cable
Cat 3 jack
110 punchdown tool
Hand held termination aid, if available

 Lesson Plan Links

Home Page

Cat 5 - 110 Punchdown Block

Cat 5 - Jack

Cat 3 - 66 Punchdown Block

Cat 3 - Jack

Cat 3 & Cat 5 - Plug

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You will need to terminate jacks for small patch panels (1) and work area outlets (4).



Jacks generally have 110 - style punchdown IDC connections for the wires, so they are terminated similarly to 110 blocks.

When you are installing Cat 3, you do not have to be as careful with maintaining the twists in the pairs like Cat 5.


Cat 3 Jacks have as many as four wiring configurations, usually detailed on the package. They only apply to Cat 3 jacks, since they do not have internal "twists" to confuse you!

Most Structured cabling installations will use T568A or T568B, while telephone systems us USOC.

Simply follow the color codes on the package to get the pinout correct!

Begin the process by stripping the jacket from the cable, but, for jack termination, you should only expose 1-1/2 inches (37 mm) of the twisted wires.

Like for the 110 block, untwist the pairs for placing in the slots of the jack.

At this point it is important to realize that separating the wires does not follow the same BL-O-G convention as a punchdown. The pairs are split up at the jack to minimize crosstalk.



Slide the jack into the hand held termination aid and hold it as shown. This will provide a steady platform for holding the jack, lining up the wires into the punchdown slots and punching the wires down.

Here's the EIA/TIA color codes for Cat 3 jacks:


Press the wires into the slots with your finger, ordered according to the color code of the termination type you will use (T568A or T568B.) Follow the color code exactly.


The pin numbers should be molded on the jack, but if they aren't use the drawing at the left to remember the order. This drawing is looking into the jack socket, so just hold the jack toward you to see where the #1 pin is located.

 Some manufacturers make jacks that can be terminated without a punchdown. They use the plastic cap on the back to push the wires into the IDC contacts - usually with a pair of pliers to insure the full insertion. If you use this technique, remember to cut the wires to the proper length and still maintain your twists close to the jack.


Once the wires are in place, use the punchdown tool to make the connection and cut off the excess wire.


Snap the plastic cover on the back of the jack and it's complete. You can now insert it into the work area outlet box or patch panel.


Your completed jack can now be snapped into a wall outlet box or a patch panel. 



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