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Punch Down Blocks (Telephony or Ethernet Cables)

  1. Apr 20, 2012 #1
    I hope this is the right area of this.. Guys, I need to know... what does a Punchdown block do? I see these in wiring closets, where the telephone or ethernet cable is flayed open, and the wires inside are stuck into the blades of the block. I'm studying for the Network+ exams, and they mention punchdown blocks for 66 and 110 styles, but I can't find a straight answer to tell me what they do, and how they are used and most importantly, whats the point of them. Any help would be appreciated. I've read the wiki, and I can't seem to get a reasoning on WHY we use them
  2. jcsd
  3. Apr 21, 2012 #2


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    From Wikipedia.org


    Also see: 66 Block and 110 Block
  4. Apr 21, 2012 #3
    :grumpy: Look I already said in my post that I had read the wiki and I need some one to explain it. Not to rant here... and I know I"m the one coming to you to ask you of your time, but people posting wiki's as answers shouldn't be allowed. We all know wikipedia, but sometimes the language isn't as clear. It's easy to just copy and paste a wiki link.
  5. Apr 21, 2012 #4


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    Uh ... what part of

    do you not understand?
  6. Apr 21, 2012 #5
    It's use in a practical sense.. when would you need to connect wiring, is it used a hub like in a computer system? Where are they generally located?
  7. Apr 21, 2012 #6


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    Okay then. 66 and 110 blocks are used for organizing twisted pairs in patch panels, etc.

    Thanks for letting me know that you don't approve of my posting techniques. Next time I just won't reply to you. :grumpy:
  8. Apr 21, 2012 #7
    Basically, they serve as centralized wiring distribution. They also assist troubleshooting efforts.

    There are various ways to implement them, but for simplicity, just imagine all of your servers, routers, etc. on one side, and all of your users on the other. Changes to wiring on one side doesn't disturb the wiring on the other side.

    (In practice, I've only used them for telephony. I have just a general knowledge of their use in computer networking.)
  9. Apr 22, 2012 #8


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    because the old style of having to solder 1000's of connections was labourously SLOW

    I have wired up many huge frames of so called punch down blocks, more commonly known as Krone blocks. we could easily terminate 500 pair a day compared to many days if it was using the old solder or wire wrap styles.

    The Krone blocks make it very easy to push in the appropriate test pin modules that were used for separating internal and external cabling etc

    like many other things in electronics, its all about economics and saving labour costs the ease of testing was the icing on the cake

    And for these left field comments of yours...
    WAY WAY too many just dont bother doing a simple google or wiki search
    they expect some one just to hand them all the answers on a silver plate without having to do any form of research themselves!

  10. Apr 23, 2012 #9


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    Most times that I've used them is as across connect. Your incoming lines (usually telco lines(66 block ) ) go to the left hand outer connection on a block(A) and your outgoing (to station) on the right hand on another block(B). Then you cross connect the incoming(A) to the outgoing (B) using twisted pair. You then install a bridge clip across the center connections. (If you have a RJ31 that needs to be installed it goes in place of the bridge clips). This completes a circuit, and has the advantage of moving an extension with out having to disturb the in and out wiring(useful in an office setting where whole depts. get moved frequently). As for the 110 blocks the same idea but it uses stacking headers to create the cross connect.
    Companies will terminate network cables to a patch panel, and then a cable goes from the switch to the port going out to the workstation.
    If a person needs a special port (pots modem, fax, poe etc) it is easy to change without major disruption.

    I know my explanation probably is confusing, but once you get see them up close they are easy to understand.

    P.S krone is a manufacturer who uses a special blade for punching down. Two others are panduit and bix that use proprietary blades.
  11. Apr 23, 2012 #10


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    Please mellow the response, NA. 95% of the time, posts like this are because posters haven't actually read the articles and followed the links in the articles.

    I think this is the key point. For those of us who have done hours of wiring on punch-down blocks, and have actually jiggled the metal insulation-displacement connector (IDC) metal pieces, they are pretty intuitive in what their function is. Maybe there are some YouTube videos, or some videos that can be found with a Google Images search that would help you get an intuitive feeling for how the connections are made. When you jiggle the metal IDC pieces in the punch-down block, you can see what pieces are connected.

    Hope that helps.
    Last edited: Apr 23, 2012
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