Physical difference between Cat 5 and Cat 5e cabling?

Question

(This isn't really server-related, but it seems more appropriate here than SO or SU.)

When we had this house built, we had network cabling run inside the house, or so I'm lead to believe. It's currently hooked up to the phone line.

Unfortunately, the builder/electrician did not say what type of cabling it was. So, is there any way to tell physically (i.e. from the properties of the cable, or the connector) what type of cable it is (Cat 5, 5e or unlikely 6)?

Picture here: http://www.flickr.com/photos/rmccue/4082179025/

Answer 1

From looking at your pictures, it looks as though you have cat5(ish) wires in the walls and a totally wacky termination at the jack.

You should put a tone generator on each plug and see if it is a single continuous run of wire from jack to jack in your house.

I'd be willing to bet that it is wired in such a way. This sort of topology would work fine for voice but not at all for data.

In such a case, you can probably replace each single "cat5" jacks with a pair of cat5 jacks and terminate each end properly. From there you can connect a switch to each port and get ethernet from one end of the service to the other.

This would be significantly less work than running new wires and give you marginally decent connectivity. It wouldn't be nearly as good as a traditional hub and spoke topology, but it would be much better than wireless...

Good luck!

(allow me to add: In no way is this acceptable work. If I were at a commercial site or if I had just paid someone to do that work, I would tell them to do it over again. Given that this is old work in a residential site, and given that a typical domestic situation's "data" budget is quite a bit smaller than even a small business, I'd be inclined to try to make it work before throwing in the towel and opening up the walls.)

Answer 2

Gigabit ethernet runs fine on cat5, so long as it really is a cat5 installation.

Sometimes 100mb runs fine on something that isn't really cat5, or if you only have 2 pairs hooked up, and then when you put gig devices it fails, but that's because the cables aren't even cat5.

Worst comes to worst, you have to reterminate the ends because the installer didn't terminate them properly (typically by hooking up only 2 pairs or by untwisting 8 inches of the wire or other lazy nonsense.)

Lastly, they haven't made cat5 since 2001 and I haven't seen a cat5 cable that wasn't really old in years. The differences tend to be the number of twists per foot and slightly better quality control on the terminations.

If it is cat5, cat5e, or cat6, or cat6a, the cable will be round and smooth. If it is cat3, it will likely be lumpy and it often kinks or has non-smooth radius bends. If it is something wacky like thermostat wire or similar, there probably won't be 8 wires coming into the jack.

In other words, don't worry about it.

Answer 3

Cat 5 was made obsolete. The Cat 5e specification specifically added some bits that defined specs for crosstalk. In theory, if you have a horizontal run of cable that bumps up against the 90 meter "limit", Cat 5e should be less latent than Cat 5.

In your situation, the difference is nominal. Being that it's a home setup, you probably don't have 100 meters of wire in any one run, so you wouldn't see any noticeable difference. The only "physical" way to determine if you have Cat 5e (if you were REEALLLYYY curious) would be to look at the jacket on the cable. The cable type is usually printed right on the jacket itself.

Answer 4

Cat5 - five twists per inch.supports 10/100 ethernet.

Cat5e- five twists per inch; pairs are also twisted around each other.support 10/100/1000 ethernet**

Answer 5

hook up gigabit interfaces at both ends and use iperf to measure the speeds. alternatively, rip out some cabling to read what's printed on it.

Answer 6

In the photograph it looks like there might be some slack inside the wall. Can you pull out a little more and read what's printed on the cable jacket?

Is this a structured cable system? Are there multiple runs terminated at one end in a common box? Perhaps there is more exposed cable at that end.

You won't be able to tell the type of cable by its physical properties without extracting a sample and measuring things like wire gauge and twist lengths.

Answer 7

Easiest way to tell cat5 and cat 5e apart is to look at the number of twists in the green pair. If the green pair has the same number of twists as the orange and blue pairs, then it's cat5e, if it has the same number of twists as the brown pair, then it's cat5.

You may be interested to know that only two pairs are used for data transfer, the others are POE. I've never tried it, but apparently you can network two computers over a single cable using only pins 1-3 and 6 on your plugs.

Answer 8

It may be possible to physically examine the cable without disconnecting the phone line by unscrewing the jack plate from the wall and pulling it out. Whoever installed it probably had some slack leftover (~6 inches), which will be stuffed into the wall behind the plate. You should be able to carefully extract some of the slack to see whether or not you can find the manufacturer's markings on it. The phone line should be able to stay plugged in the whole time.

Answer 9

The picture is too dark to tell much. The termination looks like they untwisted the wire too far back (1 inch is the limit, I believe) to meet Category 5 specs.

The jacketing on the cable will say what type of cable it is, assuming it's any name branded cable (Belden, etc) at all. If it doesn't list the spec on the cable jacketing I'd consider re-terminating a couple of jacks as other people have suggested and trying some PCs w/ gigabit Ethernet cards on it with.

Someone mentioned opening up walls to replace the cable. That's probably a little bit overkill. Assuming your local building codes allow you to do low-voltage data cabling work yourself (check with the local electrical inspector), use the existing wire as pull wire and pull some name-branded Category 5e or 6 wire yourself. Get some good 110-style jacks and wall-plates, a small patch panel, and a 110-style punch tool ($200 - $300 in materials, assuming that you don't have more than about 12 terminations) and reterminate everything yourself. It's really, really easy to do and you won't need to open up any walls.

Edit: After doing some reading re: affixing wire to studs with staples, I've found a number of references to "horror stores" about cable installers ruining Cat 5 cable runs with staples, wacky terminations, etc. It sounds like a roaring nightmare. If you do get your cable to work for networking, great. If not, I'd guess you're another person in that group of people who got screwed by a cabling installer who didn't know what they were doing installing data cabling in a residential environment. Sounds like "terminated and tested for category 5 or better compliance" should probably be in the contracts on residential cabling installation work.