What is Cat5e?

Everybody knows, if you’re still dealing with Cat-5 to use Cat-5e. I mean, Cat-6 would be better, but it’s still really expensive to have installed. So we use Cat-5, except it’s ENHANCED for that extra special protection against interference and crosstalk. But what is it? What, if any, is the actual, real, honest-to-God, difference between Cat-5 and Cat-5e? I’ve read the wikipedia entry, and while informative, it could really do with a rewrite. One of the few sections that mentions Cat-5e is The Cat 5e 350mhz debacle. The title makes me believe that maybe the 350mhz denotation is how you can tell, but then it goes and says this:

“Although the performance of this new 350 MHz cable was slightly better it was an easy way to sell the consumer on future proofing their needs while charging around 15% more and leading to a higher margin on the 350 MHz cable than the standard 5e cable.”

Well, alright then, what IS a standard 5e cable?

I looked at some more resources, and found some sadly incorrect suggestions and no real answers. For instance, this wiki answers post says that you need Cat-5e to get Gb/s speeds, that 5e is rated at 350mhz, and that there’s less crosstalk (though it doesn’t say why). Of course, it also says “Unless every single component in the network is gigabit rated, then you will never have a gigabit network, because your network will always run at the speed of your slowest device.”, so you can understand my skepticism.

The second table on this page sounds pretty solid, basically displaying that there are standards for Cat5E that don’t exist for Cat5, with the assumption that the cable meeting those standards will perform better/faster than a cable without those particular requirements.

But of course, I wanted to ask, because you can’t trust everything you read on the internet. Case in point? connectworld.net, who either desperately need to update their page, or desperately need to stop taking drugs:

“The Simple Answer:
CAT-5 is rated to 100M
CAT-5e is rated to 350M
CAT-6 and CAT6e is rated to 550M or 1000M depending on your source
CAT-7 is supposedly rated to 700M or presumably 1000M

Today there is no approved CAT-6 or CAT-7. While some folks are selling products they call Level 6 or 7, there aren’t even specs for them, making CAT-5e the best available option.”

Sad, really. I blame the schools.

So now I ask you. I assume that there is an actual, real difference between Cat-5 and Cat-5e. what is it?

It appears that Cat-5 cable is defined by the TIA/EIA-568-A standard. The only time I’ve ever paid attention to that standard was when crimping my own ends, because TIA/EIA-568-A specifies the order of the wires in the RJ45 (really 8P8C) end. It also uses the green pair first, which I thought was weird, since I learned orange first.

However, when I go to the TIA/EIA-568-A wiki page, I’m redirected to the TIA/EIA-568-B page. At a table way down at the bottom are the lines:

Cat 5: Currently unrecognized by TIA/EIA. Defined up to 100 MHz, and was frequently used on 100 Mbit/s Ethernet networks. May be unsuitable for 1000BASE-T gigabit ethernet.

Cat 5e: Currently defined in TIA/EIA-568-B. Defined up to 100 MHz, and is frequently used for both 100 Mbit/s and 1000BASE-T Gigabit Ethernet networks.


I still don’t know what the actual difference is, aside from orange going first in Cat-5e, apparently, but hey, more light on the subject, I guess.

Also, it appears that Able Cables had someone research a write a paper on the differences on the difference between TIA/EIA-568A and TIA/EIA-568B. Here is his conclusion:

9.0 Conclusion

Historically 568B was the specification on choice due to its early development and implemented base, but as the market and the political climate has changed over the years 568A has become the more dominate and preferred specification. This is only due to a desire by world standards organizations to provide a specification as backwardly compatible as possible. All new installations should be carried out using the 568A standard and cables only to be terminated to 568B specification on existing 568B systems.

Honestly, I’m not entirely sure what to make of that.

Can anyone here with more cable experience give me a hand?

BTW, I also posed this question on serverfault.

  • Obviously, the difference is one is “Enhanced”.

    For some reason this brings to mind the “Yes you do…. you don’t ask dumb question” line from http://www.youtube.com/watch?v=CE2PsfeQm-0

  • Nick,

    I just can’t leave well enough alone. I have questions that bother me! I need answers! I need to find reasons and understand things.

  • Funny, I learned cat-5e has an extra armor (for better isolation/protection) which is better suited for enterprise-use especially in buildings where more interferences might be involved.

    Now that I’m looking closer between cat-5 and cat-5e cables, I do have at least one cat-5 cable with armor… :-) But I think it’s true for most of the cat-5 cables.

  • AJ L.

    I wish I had a newer version of this book (which I think I will pick up soon) but per Newton’s Telecom Dictionary 16th edition (published in 2000) it has the following:

    Cat5: CAT5 cables can be of various guages, and are useful in support of applications requiring a carrier frequency of up to 100 MHZ. And etc. info.

    Cat5e: CAT5E is intendended to be manufactured according to tight specifications in support of signaling rates of up to 200 MHZ over distances of up to 100 meters. Specifications call for a tighter twist, electrical balancing between pairs, and fewer cable anomalies, such as inconsistencies in the core diameter.

    But again, like I stated above this book is from 2000 and I’m sure the newer 24th edition that is out has a lot better description and guidelines.

  • My understanding was that Cat5e had more twists per inch than Cat5, thus providing better protection against interference.

  • Anthony

    @Jared: That’s what I was led to believe as well.

    I think though, AJ L. probably has the most accurate description.

    Or in other words, A Cat5 cable COULD in fact meet Cat5E standards, even though it isn’t branded/marked/guaranteed to be that way, while a Cat5E cable has specific requirements.

  • AJ L.

    Just bit the bullet and bought the 25th edition that came out last year of Newton’s so I’m looking forward to seeing what it has to say about this subject compared to what it did in 2000.

  • Assuming a non-professional end-reader the warning seems reasonable, most if not all home networks rely on wireless hubs as the local backbone. As well one very well has to have both ends terminating in gigabit capable nics.

    I would also like to point out that said answer was written by someone trying to promote this website http://www.cat-5-cable-company.com/ And they do make a point of trying to explain the problem to laymen which would reinforce the simplified answer.

    Mind you I could be completely wrong.

  • I should also mention that your XML tags are broken, I just used the blockqoute and it somehow managed to swallow my post, mind you it might have been the openId transition that did the eating.

  • WarII: Thanks, I’ll test it here:

    This is a blockquote

    That seemed to work.

  • Ok then it must have been openId that stripped the xthml, which isn’t that surprising since noscript also throw a wrench in as well.

    PS: Matt you should know my name is warLL by now!

  • AJ L.

    Well got my Newton’s 25th edition today and am somewhat disappointed in the fact that it’s explanation between Cat5 and Cat5e has not changed hardly at all from its book that I own from 2000 to this book published in 2009. Only thing that it changed was that Cat5e is now becoming the standard for cabling.

    It also states that it supports rates up to 100 MHZ over distances of up to 100 meters which I believe the prior edition states 200 MHZ but I’ll have to double check when I get back to the office.

    It does have a section approximately 2x the size explaining Cat6, then goes to Cat6e, then Cat7 but that’s another discussion….

  • RC

    The difference between cat-3/5/6/7 etc., is the number of twists-per-inch. This difference is obvious with striped 3 & 5 cables side-by-side. These are balanced cables, so the most twists per inch, the better rejection of interference/cross-talk, and the higher the frequency response. Other changes between the specs are negligible.

    Cat-3/4/5 were traditionally a standard step size increase from each other… an doubling of frequency, IIRC. With Cat-5E, they went for a partial-step in twists-per-inch instead, and didn’t really specify how the better frequency response, promoting it for reduced interference instead.

    The confusion about whether gigabit ethernet requires CAT-5, CAT-5E, or CAT-6 quite simply stems from the fact that there were two notable gigabit standards early-on… One used just two of the four pairs, as 10 and 100BaseTx did before it, and required slightly higher grade cables. The other used all 4 pairs and could be used with regular CAT-5 cables, though perhaps with limited range. The latter won out in the end.

  • http://www.ablecables.com.au/568avb.htm#_Toc426467840 is consistent with my memory:

    7.1 Comparing 568A and 568B

    By looking at the first two specifications we see that the only difference is that the green and orange pairs are terminated to different pins, there is no difference as to what signal is used on what pin, only what colour wire is terminated onto it. So technically the standards are the same, they operate in the same manner and neither one is technically superior to another when used in Ethernet applications.

    It is when an Ethernet system and a phone system are combined that the difference really becomes apparent.

    So, 568A/B is just a wiring standard, and if you have one end A and one end B, you have a cross-over cable, which I’m pretty sure was obviated by 100baseT. I learned to crimp CAT5 cables that were TIA-568A on one end and terminated to operate through buildings wired CAT3 USOC. We had special “splitter” dongles for offices with two workstations, since at least in the 10mbit days you only needed 2 pairs per Ethernet connection, and then we terminated the patch cables in the data closet to have two heads.

    But reading your post I’m going to figure CAT5 is rated to 100M and CAT5e is rated to 350M, but figure that if you’re wiring a building try to have closets to terminate at 100M anyway.


  • I’m pretty sure they just updated the spec to tighten the restrictions a bit. Some of the stuff I was buying as Cat5 became Cat5e without any change in the manufacturing process (confirmed with the manufacturer). In other words if you were already buying decent quality cables called Cat5 you’re probably getting nothing extra out of Cat5e. This would be loosely confirmed by the lack of a price difference found at the website posted above: http://www.cat-5-cable-company.com/faq-cat5-v-cat5e.htm

    I’m also pretty sure TIA-568A vs TIA-568B difference has nothing to do with Cat5 vs Cat5e. The 568{A,B} difference was definitely around when I was doing my CCNA, years before I’d heard of Cat5e.

    As for a link to prove my statement… I’ve got nothing.

  • Just chiming in to say I was always taught that the difference was in the twisting of the Cat5E making it more EMI resistant.

  • Phil

    My understanding is CAT 5E as guaranteeing performance of attenuation

  • i am sure that you are right talking about cat5e is the best cable in the market.
    thanks for the standard type information.