Please help me understand punchdown blocks and patch panels.
March 3, 2008 5:56 AM   Subscribe

Help a new homeowner configure LAN in utility area. I'm new with punch blocks, patch panels, etc.


First I'd start of with me: I'm experienced in basic networking. I can run the line, make my own ethernet ends and am familiar with switches, hubs, routers, etc. What I am not experienced with are patch panels, punchdown blocks and the like.

My new home is pre-wired with cat 5e for the phone lines and ran to a central location in my utility room. I want to convert some of those lines into computer network lines. First I'll replace all wall jacks to rj-45 from the current standard rj-11 phone line jacks since you can plug rj-11 into rj-45 jacks. When all comes to the utility room, I'll simply select which jack I'd like to be the phone line and wire it as such.

Now here in the utility room is what I'm not too sure of. What I'd like to be able to do is if I change my mind and want room a to be telephone, I'll simply unplug something in my utility room and plug it back into something else. And wala, it's been changed from ethernet to telephone. And the other way around also. A super easy way to change things back and forth in the utility room.

So is that via a punchdown block? A punchdown block with rj-45 jacks on it? Two switches - one for ethernet and one for phone?

I've been trying to find some handy tutorials on the internet, but thus far have found nothing.

Thanks all,

posted by Jackie_Treehorn to Technology (19 answers total) 3 users marked this as a favorite
Here's the normal way of doing this:
- Run your cat-5 from each room into a big patch panel in the utility room. Your patch panel would have labels like "Living Room", "Kitchen", etc.
- Install a second patch panel in the utility room, for your phone lines. A punchdown block is basically a phone line splitter, so run a series of lines from your punchdown block to this second panel. It will have labels like "555-0001", "555-0001", "555-0001", "555-0002".
- Install a network switch in the utility room, for your network.

Now that you've got that all set up, to make any given jack a network jack, use a short cable in the utility room to connect "Living Room" (say) to the network switch. To make it a phone extension, connect "Living Room" to "555-0001". All this wiring is done with Cat-5, since all your patch panels are Cat-5 - you only use RJ-11 if desired at the very end, in your jack in the living room.

Also, be careful that you never connect a data device to a telco jack, since the device can be destroyed by the phone line voltage.
posted by pocams at 6:31 AM on March 3, 2008

This seems helpful.
posted by electroboy at 6:32 AM on March 3, 2008

What odinsdream said. I just have a terminating 110 block for all jacks. I can then cross connect to the ethernet 110 block or a telephone 110 block depending on the application. Be sure to label the port.
posted by toomuch at 8:28 AM on March 3, 2008

I did this 2 years ago in a new home we moved into. I found a friend who had a few network tools because the lines were not clearly labled in the junction box as to where they ended up. He had a lttle do-hickey that you plugged into the jack, and then one into the end in the utility closet and it told you if you had a matched line. If I didn't have that tool, the job would have been next to impossible. He also gave me a punch tool to get the cat-5 wires into the punch blocks, and that tool was indespensible. What I ended up doing is leaving the lines I wanted to use for phone attached to the patch panel (which was designed for phone in the first place, I don't think data would have run through it. and yanked the lines I wanted to use for data right off the patch panel. Then I put some male jacks on those cat5 lines I use for data and popped them into a 5 port $30 netgear gigabit switch. Runs perfectly. My router and DSL patch in through the switch.

IANANE, so that's why you get all the do-hickey terminology, but I remember having a great deal of trouble finding a resource online to help the non-network engineer figure out these home networks. It's great that they wire everything for data, but to leave it like my builder did...I'm probably the only homeowner in the development who didn't just plug in a wireless router to their cable modem and call it a day.
posted by johngalt at 8:40 AM on March 3, 2008

FYI, as long as you don't have two phone lines, its really not THAT big of a deal to mis-wire. Ethernet used 1,2,3, 6. Phone uses 4,5. So, if you do accidentally plug something in wrong, it's not that big of a deal as long as you catch it fairly quickly. (Phone line #2 will use 3 & 6).

4 pair straight through provides the maximum flexibility.

2 other tips.

1) Get a "LAN cable continuity tester" that's about $40 or so. You can then check to ensure that its a straight through run. Sometimes the punch down block and the jacks that you purchase won't be mated. So, there's a bit of trial and error to figure it out. But, as long as you've got that sorted, you'll be in good shape. It will sort out any crossed pairs quick. :-)

2) Keep an LONG Ethernet patch cable that can run all over your house. Mine is over 100' long. If I'm running into problems with a peripheral or a line, I can quickly test it and see if its the device or the jack.
posted by wflanagan at 8:51 AM on March 3, 2008

FWIW, running a line is a pain. Running 2 lines is just slightly more of a pain. If you are going to bother running a line, you might as well run two- then you can set up RJ45 on one and RJ11 on the other- or even RJ45 on both.
posted by jenkinsEar at 9:03 AM on March 3, 2008

If the house is prewired, what's the utility room currently look like? All those cat-5e runs must terminate on something. I assume it's a 66 block with all the phone lines multipled down it?

You want to terminate the closet end (even if it's a utility room in reality, it's called a wiring closet) on a patch panel, so it's all RJ45 on front. Then you mount your ethernet switch next to it, and go between them with patch cords.

For phones, you'll wire up another patch panel with the phone lines multipled between all the jacks. Then to bring phone service to a run of house wiring, just put a patch cord between the two patch panels.
posted by Myself at 9:46 AM on March 3, 2008

Response by poster: Myself,

All of the cat5e cable that has been run in the house comes to one bundle in the utility room. from that point all wires are exposed and two wires from each cable, blue and blue white i think are connected with another cable that leads out side where the phone company will install their stuff.

They are not connected to a block of any kind. I think they are just wire nutted together if I remember right.
posted by Jackie_Treehorn at 10:10 AM on March 3, 2008

They just hang in a bundle? That's gross. Whoever did that should be embarassed.

Get a patch panel. Twice as many jacks as you have runs is a good rule of thumb, because:

You're going to start by punching each run down to its own jack, following the regular color code, using the regular punchdown blade that cuts the wire after seating it in the contact. So if you have 10 phone jacks in the house, then jacks 1 through 10 on your panel will take those.

Then, you're going to flip the blade end-for-end, so you're using the one that doesn't cut the wire. Strip the outer jacket from a few feet of scrap cat-5, and snake it back and forth in the other jacks. Say you've got a 24-port panel, so start at port 24 and use this dont-cut blade to punch this wire into jacks 24, 23, 22, 21, etc, so they're all connected in parallel.

Now, run a single phone cord from jack 24 out to the phone company's thing. Voila, your phone line(s) appear on all those jacks at the end of the panel.

So now, if you want phone service in rooms 2 and 5, just use short patchcords to plug between jack 2 and 23, and between jack 5 and 22, for instance.

I hope that's clear. If not, I could mock this up with some spare parts and take some pictures...
posted by Myself at 10:47 AM on March 3, 2008

IANANE, so that's why you get all the do-hickey terminology

That device, if I am reading your post correctly, is called a toner tester.
posted by damn dirty ape at 11:18 AM on March 3, 2008

Response by poster: Myself,

First - thank you (and all of you) for helping me out and teaching me something new. I really do appreciate it.

I think I'm following you on this. I'm not quite understanding the part about the scrap piece of cat 5 and snaking it back and forth however, so photos would be very nice for that bit. But I do indeed grasp the concept you are describing. And as I understand it, this would cover the phone side only of the networking.

How would I integrate this part with a home computer network and a switch? Would I need yet another patch panel to accomplish this? To be honest, we are more likely to have just one jack in the home be dedicated to a phone jack as we use 1 base phone and then 3 other wireless phones that do not require a jack. They just phone home to the base.

Would/could you accomplish this with the use of a punchdown block instead of a patch panel? The only reason I'm asking is that cost is somewhat of an issue and I'm trying to be very frugal with this and it seems to my inexperienced eyes that patch panels are more pricey than punchdown blocks.

Thanks again,

posted by Jackie_Treehorn at 9:44 AM on March 4, 2008

Best answer: Okay, through the miraculous power of MS Paint, I've doodled up an explanatory graphic for your edification and my embarrassment. ;)

You already know that each cat-5 cable has four pairs in it, and that they're colored blue, orange, green, and brown. Within each pair, there are two wires, so a blue/white and a white/blue twisted around each other make up the first pair, orange/white and white/orange make the second pair, et cetera. I've only drawn single lines to represent pairs, because drawing twisted pairs is a pain in the ass.

Each jack is represented here by a square where the RJ45 connector plugs in, and a rectangle with four colored terminals on it. If you look at the back of a patch panel you'll see something very much like this.

I don't know what color your house's cat-5 is, but sky-blue is common, so that's what I drew here. The cables dropping into the closet are terminated onto the first few jacks, using the regular punch-and-cut side of the blade. (From the point where the jacket is stripped, each colored wire/pair goes to the punch terminal, and stops there.)

So in this example, you have five runs going out to rooms in the house. Rooms 1 and 5 are getting phone service, rooms 2 3 and 4 are getting Ethernet. So the green network switch on the right is cabled, with short burgundy patch cords, to the appropriate jacks.

The trick I've done with jacks 9-12 is that I've turned them into a splitter. Using some scrap wire (just yank the jacket off some spare cable), punch them down on jacks 10 and 11 using the dont-cut end of the blade, then punch on 9 and 12 using the punch-and-cut blade. I hope the illustration is clear here. Then a single cord from Ma Bell to jack 12 brings phone signal to the others in the group. The patch cords from 9 to 1 and from 10 to 5 bring phone service to those rooms. Got it?

Now, that's the Right Way to do it. It's robust, because you can easily test or trace any run to isolate problems. It's versatile, because you can repurpose any run at any time simply by changing what's plugged into it. And it's reliable, because once the house cables are punched down onto those jacks, they never move, so there's no fatigue on the connections.

Since you're planning to use a single-base-station cordless phone setup, much of the versatility of this method is superfluous. You could just crimp an RJ45 connector onto each house run, and plug all but one of them into your wall-mounted ethernet switch. The one that serves the phone, you'd just plug into an RJ45 coupler, and into the other end of that coupler you would shove the phone cord headed out to Ma Bell. No need for a splitter or bus arrangement to serve multiple locations.

HOWEVER, crimping RJ45 plugs onto the house cable is a bad idea, UNLESS you get the ones specifically designed for solid wire. The wiring in the house is solid wire, which is more affordable, and well suited for punchdown termination. Patch cords are normally made with stranded wire, which is more flexible, and takes a crimp well but doesn't punch reliably. At the near-microscopic scale where the crimping tool forces the contact into each conductor, things work a bit differently depending on whether the conductor is stranded or solid. Most RJ45 plugs are made for stranded wire because they're intended for building patch cords. Stress or movement on solid wire, because it is stiffer, will be transmitted into the connector and work the conductors loose from the crimp, leading over time to flaky connections. A lot of networks are built this way and run just fine, most of the time. Go the cheap route at your own risk.

Okay! Now ask more questions! :)
posted by Myself at 7:26 PM on March 4, 2008 [1 favorite]

Oh hey, cheap! The most recent MPJA catalog came in yesterday and I just found a 24-port patch panel for $20. That's cheaper than I'd been able to find even on the 12-port models. (They also have 3-foot patch cords for $0.49 each. Stock up.)

For a punchdown tool, see if you can borrow one. The cheapies I'm finding on eBay have a fixed blade that always cuts on each termination, they don't accept standard Harris blades of the style that you can flip around to use the non-cutting side of the blade. (I did find one that explicitly shows its reversible blade, for under $10. It doesn't appear to be a standard blade, but that's not important since the included blade does everything you need.)
posted by Myself at 3:47 AM on March 5, 2008

Response by poster: Myself,

You nailed it! Very nice, thank you! Good artwork to boot!

I completely understand what is going on now. The cost for that patch panel is in my range for sure and the patch cables are good as well.

I don't know exactly how many runs I have in my new home right off hand, but let's just say I have 10 runs. The 24 port panel you suggested would be just fine in that instance. Then I could have 1-12 for ethernet and 13-24 for the phone system and be able to switch back and forth to my hearts content.

If in that same example I had 15 runs, would you then recommend - for the same simplicity - I purchase 2 of the above mentioned patch panels? One for the phone system and one for ethernet?

I haven't surfed that mpja site too much yet, but is there a mounting bracket for that patch panel. I'd like to place a piece of plywood on the wall and mount a bracket with the patch panel and shelving for switches, modem, etc to it.

I'm a bit of a perfectionist and a neat freak. I'd like this to look like someone who really knew and cared what they were doing installed this system.


posted by Jackie_Treehorn at 9:54 AM on March 5, 2008

Response by poster: Also,

Could anyone recommend two pieces of equipment for me?

1. I'd like to find a decent punch down tool for this job.

2. I'd like to have a ethernet tester or tracer or whatever you might call it. Something I could place in bedroom 1 and then go down stairs and plug it into the cables until I found bedroom 1 and label it correctly.


posted by Jackie_Treehorn at 9:58 AM on March 5, 2008

Best answer: Panel sizing: Rooms that get ethernet only use one jack, the one where they terminate, and then the other end of their patch cable goes to the ethernet switch. Rooms that get phone actually take two jacks, one for the run to terminate on, and one that gets used as a "splitter port". Then add one for the Ma Bell connection.

So if you have 15 rooms and you plan to put computers in 12 and phones in 3, then you'd need (12+3+3+1) = 19 ports. The 24-port panel should suit ya just fine.

The punchdown tool I linked would be ideal. It comes with a reversible 110-style blade, which is all you're dealing with. (Phone geeks also sometimes deal with the older 66-style blocks, and would want a tool with both types of blades, but you don't have to worry about that.) Except that auction's about to end, so here's another identical one from the same seller. (No relation or endorsement other than "this looks appropriate".)

For the tester, I recommend Test-Um brand. I'm fond of my LanRover but it might be overkill, and it looks like the Net-Rite now implements the same feature set, plus a better display, for half the price. That sucker will save you a *ton* of time if, like most of us, your terminations aren't always perfect.

That sort of tester is for verifying the wiring of cables that're already terminated. If you want something you can just wave at a cable to see if it's the one you've stuffed the remote into, you're talking about a "toner and wand". Test-Um makes one of those too, though the Progressive/Tempo/Greenlee classic 77HP/200EP combo has been the standard for decades, for good reason. I don't think you need this, though.
posted by Myself at 5:59 PM on March 5, 2008

Brackets: You can get a swing-out wall mount bracket for another $twentysomething, but hell, you already paid that much for the panel! Up to you, I guess.

Some of the panels I was seeing yesterday while searching around, instead of being rackmount style, were designed to screw straight to a plywood backboard in a wiring closet, and included a standoff bracket and everything, all sized to fit in a standard 66-block footprint. I think that was only 12 ports though, because 24 in that footprint just doesn't sound doable.

Now that you know what you're looking for, I'm sure you can find the right parts to fit your sense of budget and aesthetics. The panel at MPJA is an unusually good price, so that might be the best option even if it's not technically made for wall mounting. Hey, if you have a local Graybar outlet, stop in there and see what they have. Or shanghai another customer (they cater to telecomm techs) into helping you decide. :)
posted by Myself at 6:07 PM on March 5, 2008

Response by poster: I've ordered some to the suggested products. In a month or so when we move in and I get everything unboxed, I'll post again with results and photos of the installation.

Thanks everyone!

posted by Jackie_Treehorn at 3:38 PM on March 6, 2008

Today I ran across a good picture showing how to turn a patch panel into a splitter by connecting the same line to multiple jacks.
posted by Myself at 7:47 AM on February 5, 2009

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