I have cat5 routed to all rooms in my house from a central closet. In the closet, I have a router.

I've been connecting to a computer in room A. That connection stopped working. I connected the computer directly to the modem in the closet - it worked.

So, I suspect that cat5 cable between the closet and room A is bad. How do I test if the cable is broken, the connector in the closet is broken or the connector (bulkhead wall) in room A is broken?

Is there an easy way? Or do I need to replace both connectors, and if that doesn't fix the issue, then I need to have the cable re-run (not sure how much that would cost).

If I need to replace the connectors, what tool do you recommend for: 1) bare cable in the closet, 2) the bulk head wall connector in room A? Hopefully it would be the same tool. Oh, also parts - is there a particular brand for these connectors I should search for?

Klein (and many others) make testers that can check the continuity of the cable as well as any mismatched pairs. Mismatch isn't the problem if it was working until recently. They also make crimpers that will attach a new male end (closet). The female keystone connector in the wall would utilize a punchdown tool to replace. There are nice ones that punch and trim at the same time or cheap ones that get the job done. Many times there is a cheap tool in the package with the keystone that will work.

As you can see, there are a few different tools and testers needed to figure this out and repair. Of course, the wire could be mouse chewed in the wall halfway and replacing connectors won't do a thing. I am a hardcore DIY guy and will buy tools and learn procedures because it's fun. OTOH: If this is the only issue you have and don't care to run any more wire in the future, a Geek Squad guy with a bag of testers, crimpers and connectors may actually save you some money.

MNSIG outlines the correct process. If you want to do a quick and dirty process, have a volt/ohm meter with a continuity tester, and are willing to sacrifice a Cat5 patch cable then this process will confirm a basic connection.

1) Cut the patch cable in half. Strip the outer sheathing away to expose the green, blue, orange and brown wires.
2) On one side, strip away the insulation and twist the green to green/white, orange to orange/white, blue to blue/white and brown to brown/white.
3) Plug that into one end of your house wiring.
4) Take the other end of the patch and strip away the insulation for all wires.
5) Plug that into the other end of your house cable.
6) Use the connectivity test on your meter to test every colored pair.

At best this will only show connectivity, if there is degradation in the cable it will still connect but not transmit ethernet signals.

I have a CAT cable tester that has a battery powered unit on one end and a non powered unit on the other that will quickly tell you if the cable is good or not.

Looks like this and they are not expensive:




Could be a bad end unless something has somehow disturbed the cable along its run like an animal chewed it.

A good visual inspection of the connectors on both side M + F ends.

Check the tabs that spring up and hold the connectors in place- Make sure the connectors stay firmly seated when inserted.

Another thought?

Have you considered ditching the cable and going WiFi? Cat5 is pretty slow stuff these days (100Mb/s max), unless you have 5e, which can get to 1Gb.

I'm still getting my head wrapped around the current tech, wherein cables are often slower than wireless. After upgrading my mesh to WiFi6, I went through my stock of Ethernet cables and ditched all my Cat5 Ethernet, which for years (decades?) was way faster than any service I could get into my house (let alone bounce around inside it), but which now is less than a quarter of the speed of my WiFi.

This message has been edited. Last edited by: joel9507,

Don't just look at the terminal if the wire tester indicates a break.

I have the same problem occasionally. So far, the mouse-chewed wire has been near the end, and I've had enough extra slack to snip it off and put on a new terminal.

An old house and woodmice may someday make me learn how to get a wireless dongle to work in linux.

The "easy way" is to use a continuity tester designed for that purpose. These are fairly cheap, even the "name brands" are under $100. There are also testers that will actually measure the signal carrying capability of the cable, but these are much more expensive (four or five figures).

First, check the leds on the ethernet ports, make sure that both ends see a good signal. Then, swap the "bad" cable with a known good one, doesn't have to be in the wall, to verify that it is the cable path that is the problem rather than, for example, an incorrect router configuration, or network interface configuration on the affected device.

Often, a "bad cable" is due to improper termination. Cutting the plugs off each end and putting on new ones is fairly cheap and easy, but does require the right tools and careful attention to details (like which wire goes where in the connector). Having a spare mini-hub/switch on hand can be very handy for this type of troubleshooting.

As far as termination tools go, the wall-mounted jack will almost always need no more than a punch down tool for termination. The cable plugs use a pliers-style crimper. The pass through connectors where the signal wires feed all the way through the plug are much easier to wire correctly than the older style. See this Amazon link for a decent picture of how this works. The pass through connectors need a different crimper than the legacy style. This link shows a kit that has everything you will need, I'm sure there are many others. Check monoprice os ifixit if you are allergic to buying from Amazon.

Also be aware that there are two ways to wire the cable, straight-through and "roll-over." Most device ethernet ports these days are auto-sensing so it doesn't matter which wiring scheme you use, but if your devices are older, this can make a difference.

Beyond a simple "are the right wires on the right pins and all connected" tester, such as my Klein LAN Scout Jr. ($54 at Home Depot), the only way to know exactly what's wrong and at which end is a device costing 10-20 times that, such as my Fluke Model CIQ-100 CableIQ™ Qualification Tester. The latter such devices are usually cost-prohibitive for the casual user

That isn't to say a devices like the Klein aren't useful. They are.

With something like the Klein LAN Scout Jr., start by testing your jumpers at each end. Make certain They're good. Then, using the jumpers you've confirmed good, test end-to-end to see if a wire's come loose or a jack's gone bad. (It can happen that one of the little spring-loaded pins in the jack lost its springiness or became cockeyed.)

If the jumpers are good and it's something in the wall your only recourse is to re-terminate each end, one-at-a-time, cross your fingers, and pray. If it is in the wall and you're lucky: The first one you re-terminate will be the guilty party and problem solved. If you're not quite to lucky it'll be the other one. If you're really unlucky it'll be neither--in which case it means the cable's got a defect. (Yeah, that happens, too--though it's very rare.)

Of course, the other problem that can happen, and has happened to me, is terminating poorly. I have had it happen a jack went bad, I determined which jack it was (using a tool more like the more expensive tool I noted), re-terminated with a new jack, and it was still bad--only differently. Pulled the wires, snipped the ends, re-terminated again, with the same jack. Fixed.

So it can be a bit of a craps shoot. Sorry.

All the above is why, before I did a fairly sophisticated networking job for one of my best friends, last year, I popped for the Fluke CIQ-100 cable tester. Eliminates all the guesswork.

It proved its worth right out of the gate. I often build my own jumpers from bulk stranded. Had a short piece I'd cut off something. Terminated it. Put it on my shiny new tester. Bad! The thing told me which end and what was wrong. Snipped the plug, re-terminated, good.

After that I also replaced my economical Monoprice modular plug crimpers with a pricier set made by Paladin.

Thanks guys, this helps. I never noticed it but the keystone (why is it called keystone?) says it is cat5e.

Tools in the cart - ugh, total cost including connectors (RJ45 / Keystone) is $220+ - I didn't get bottom line though. Tester will do coax, RJ11/45. Buy once, cry once?

quote:

I've been connecting to a computer in room A. That connection stopped working.

Likely not an issue in a normal house, but How Long is That Cable run? I assume there's not a large coil of it as part of the run that would make it extremely long, but thought I'd ask for the sake of completion.

everything else has been well covered so not much to add.

quote:

Originally posted by konata88:
the keystone (why is it called keystone?) says it is cat5e.

Good move on the installer, thinking ahead.

Hope it proves to be an easy diagnosis and fix.

quote:

Originally posted by joel9507:

quote:

Originally posted by konata88:
the keystone (why is it called keystone?) says it is cat5e.

Good move on the installer, thinking ahead.

It's printed right on the jacks

quote:

Originally posted by konata88:
(why is it called keystone?)

terminology Goes back to the very similar telephone RJ-11 jacks which were called keystone because the hole looks like a little keystone doorway.

These were pretty cool 50 years or so ago when they replaced the old 4 pin phone jacks.

At the risk of asking a stoopid question, are you using the same cable to connect computer at the closet and the room that fails? IOW, ruled out the cable IN the remote room?