VDV Works Virtual Hands-On Training


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

110 Punchdown block - Part 1


Step 1 NEXT BACK  Examining The 110 Block

 You will need:

2 Cat 5 UTP cable lengths

Cable stripper

Punchdown Tool with 110 blade


 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

Go to the quiz


The 110 block (3) provides an interconnection between patch panels (1) and work area outlets (4).



Here is a 110 punchdown block with terminated Cat 5 UTP cables. The termination is actually a joining of two cables with the 110 block acting as a transfer point. Punchdown blocks can be used for interconnecting cables in a telecom closet (TC) and the 110 style punchdown is commonly used for terminating cables on jacks and patch panels also.

The block is a plastic base with slots for 50 individual wires, since it was originally designed for termination of 25 pair telephone cables. The block itself does not have any metallic contacts. The connections are made by a connecting block. The first cable to be terminated is punched down into the block. Then a connecting block is then pressed on top of that set of wires, and the second cable's wires are punched onto it.

When dealing with many cables in a situation like this in the field, it is imperative that every cable be labelled at each termination point. For this exercise we will only refer to a single incoming cable and its corresponding outgoing cable.



Here you can see the connecting block attached to the 110 block. One cable's wires are under the block, the other's on top. 

It is important to keep the twists in the wires to within 1/2 inch (13mm) of the punchdowns and the cable jacket within 3/4 inch (19 mm). This will maintain the cable at Cat 5 performance.


Here's a real 110 installation used for telephones. Notice how the wires are all open? They are from large pair-count cables (they come with counts up to thousands of pairs!) 




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