Untwisted Cat5e cable causing problems?

[sharkdizzogg]

Hello,

I am trying to connect my desktop pc on one side of the room to my router on the other side of the room. To hide the cables I bought a 50 ft cat5e cable from RiteAV on Amazon.com. It was a great deal at $7. I ran the cable from the router, through the wall, over a drop tile ceiling, down the other wall and into a box next to my computer. Before terminating the cable at a jack and setting it into a wallplate I tried connecting it to the computer to make sure it worked. It did but it was slow. The computer is pretty slow though so I thought it would be ok. Having passed the test I cut the plug off the end and wired the cable to the jack using the 568a setup. It didn't work. I wasn't sure which to use so I tried 568b. That didn't work either. I checked the intructions again. It said to make sure that only 1/2 in of the cable is left untwisted. I looked at the wire and none of it was twisted. I tried twisting the pairs together as maybe just the portion I could see was untwisted. It didn't work. I checked the other end of the cable to make sure it was 568b, and it was. I reconnected the cable to the jack probably 6 times before I gave up. I think the cable may not work because it is not twisted. I'm looking for some backup on this hypothesis. It took a fair amount of work to run the wire and I would prefer to not have to do it all over again. Any ideas on why the cable worked when plugged into the computer but not when connected to the jack?

Thank you for the help,
Mike Sharkey

 

[NECPBXtech30]

If the patch cable is stranded copper, and you are trying to terminate on a jack, that can cause you problems. Use solid copper cables for your horizontal runs, and stranded copper for your patch cables. Terminate a Plug back on and see if it works. the 1/2 inch twist rule is not going to matter that much on a 50' cable. (not Unless you are running 10 gig from your PC to your router.)

"However beautiful the strategy, you should occasionally look at the results." Sir Winston Churchill

 

[trvlr1]

You may find that the cable was terminated at both ends, but not to any standard, just as long as the colors match positions it would work. As you cut the end off and reterminated it on a jack, you have now introduced a standard at one end but not the other. If you cut the other end off and terminate it the same way you did the router end it will probably work just fine.

 

[buitenhek]

hold up the CAT5 cable end with the jack. Look at the CAT5 jack with the clip facing back. Note the color of the solid cables connecting to the jack from left to right. Match that same color pattern (left to right) on your far side CAT5 jack.

Regards
Peter Buitenhek
ProfitDeveloper.com

"Never settle for a job well done...always look for cost cutting measures

 

[dagwoodsystems]

What's the story on this? I'd like to see the original poster write up a resolution if there is one.

Obviously there can be a problem with color codes, standards and such, but I'm willing to bet that the factory cable that was bought, cut down and reterminated was made from stranded wire. Stranded wire [doesn't necessarily...but one will be more successful if you] should terminate it using modular plugs designed for stranded or mixed wire.

And while it's true that the "same color--same position" technique will work on any given straight-through cable, it's important to know that wire PAIRS play a role in proper transmission. It's not a coincidence that the orange and green pairs have a higher number of twists per inch than the blue and brown pairs...those pairs are used for Ethernet basics.

Could you use white/blue and white/brown for a transmit pair and green/white with white/orange for the receives. You can and it will function, but just not optimally. Doing that is called "splitting pairs" and is not at all recommended. You see, it's not just about electrons going down a wire end-to-end. At the speeds we're trying to achieve, there are other pieces of physics that come into play. Using twisted pairs for a given signalling type is one of the ways we do that.

Tim Alberstein

http://www.dagwoodsystems.com

 

[mcintosh78]

Also, did you have the cable plugged into any equipment and cut the other end off. This can cause issues as well.

 

[hawks]

If what you say in the original post is true and the cable is not twisted at all then I think that is your issue. As far as I know it is the twist and amount of per inch that make it cat5e or not. Someone correct me if I'm on the wrong track here.

 

[mcintosh78]

The issue is not with the wire not being twisted. It is under 50ft.
As in a reply early on, is the copper wiring solid or twisted? Each needs to have a specific RJ45 crimp end.
Have you tested to see if the cable is crimped correctly. Try a loopback plug in each device and see if the NIC cards are good.

 

[TouchToneTommy]

Well, the original poster hasn't been back since April 6th, 2 days after the drive-by posting. I don't think we will ever hear what happened.

 

[iolair]

One other thought - have you checked your environment? Could the cable be running near other electrical devices or interference? That could cause it to run slow. I realize that the termination is a problem, but there could be other factors at work here.

Iolair MacWalter
Network Engineer

 

[davethecabler]

A property of CAT5/e/6/7 is that the pairs are twisted together through the whole length of the cable. If you have a cable that isn't twisted then you will have major attenuation and interference that will cause the cable to run extremely slow or not at all.

Most cables that are 50 ft cost more than $7, and that is for a reason! Cheaper is not always better. Get a cable from a well known and trusted manufacturer so you can guarantee it will meet your needs.