How to test cat5/cat6 cable runs, using software-only, or simple tools?

Question

Are there any utilities or simple tools or techniques to easily test a CAT5 cable, to see how well was it installed?

Cat5 is often installed by amateurs, but has been installed and "working" for years. Proper cable testers and certifiers like a Fluke or LanTech often cost over USD$1000 and people who have them are few.

Aren't there some sort of special network cards, or USB cat5-testing devices, one can plug into a computer and test the cat5 with software? Perhaps an Intel utility for their cards?

Solution 1

Buy a Fluke cable tester, they're what everyone else uses.

Solution 2

If you are doing Cat5e/6 gigabit and your PC auto negotiates to gigabit then your data pairs are terminated correctly. If it auto negotiates to 10/100 or doesn't work at all your data pairs are out of order or incorrectly terminated.

If a file copy of a large file hits max speed, and wireshark or netstat -s shows lower TCP retransmissions (0.5% or lower is acceptable), then the wire is good. The larger the file you copy the higher the guarantee is that the cable is good.

If you need to test the non data pairs (applies to 10/100 ONLY not gigabit which uses all 4 pairs), then you will need either a tester (which tests continuity), or a certifier (which is expensive). Some certifiers only test continuity on the non data pairs anyway, so if you do the same thing it is NOT the end of the world.

Cable certifiers make finding the issue quick and easy, and make testing much quicker then a PC. They completely eliminate the possibility of PC hardware issues from the equation. The downside is the price, especially for SOHO or hobbyists.

However there are some specialized PC based testers like NetPi turning up, if you are not sure where to start as far as what software to use, and how to use it.

Passing Cat6 can be hard, if there are any kinks, nicks, etc. Also if you punch down to a keystone keep the wire twisted as close to the keystone as possible, if you untwist it too much it won't pass. Cat5e cert is good enough for gigabit, so most people are fine with this in SOHO and Hobby. But if you are charging or going to be charging people for Cat6 certified, then it should certify as Cat6.

Solution 3

If you are going to continually test cables afterwards buy a fluke you won't be disappointed. If this is a one time only call around locally to companies and IT shops see what they would charge you to come out and test your runs. You could also do some searches on Google to rent a fluke cable tester. I found a few companies that do it.

Solution 4

I think the major problem you are facing is that to test the physical properties of cables you need low level hardware access for the software which a standard laptop or PC NIC won't give you.

So you can use something like this hardware (https://pockethernet.com/) and I think you can use your own software if you're not happy with their completely adequate software, or buy one of the well know hardware testers like Fluke and EFXO.

Since you say some cables are installed and working, you can use something like https://github.com/jwbensley/Etherate to make low level Ethernet software tests.

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Comments

[Brent Pabst]

What are you looking to test? Are you just looking to see if the cable is OK or are you looking to run a full battery of tests for performance and the like? If you just want to see if a cable is punched properly they sell pretty cheap devices to do that.

[gravyface]

are you testing patch cables or cabling throughout a building? If it's the former, throw it away and buy a new one if it's homemade; no test required and much much cheaper.

[Milind R]

Forget it man, virtually all professionals have a problem with amateurs getting to use higher end functionality using cheap network cards instead of expensive equipment. They're going to repeat again and again to "buy a Fluke". I'm an EE, and I know a cable tester can do much better than an NIC in physical terms, but just for doing approximate TDR for locating faults, NICs are definitely enough. Some NICs actually do have them.

[user135698]

Want to add to my toolkit something allowing to test and troubleshoot cables in a troublesome LAN. A Fluke is just much too expensive, simple continuity testers are just too simple. Just found one bad cable now - computer worked OK, but network seems flaky. The cable apparently has bad terminations. Changed it, but just based on appearance.

[user135698]

Yes, cable certifiers are the best way. See some cheaper ones. Fluke, test-um, wavetek, microtest. Intel 82577 gigabit network cards have an "advanced cable diagnostics" with TDR, they do several tests. I ended up using "Totusoft LAN Speed Test" to benchmark the cable. Became visible it would only transfer at 40Mbits. Another cable benchmarked at 95mbits.