I have 50 feet of Ethernet cable to run from a router to a desktop (over a distance of about 25-30 feet in all), but there are no connectors/ends on the cable.
I picked up some plastic ends, but am not sure of a few things:
Does it matter if the cable remains 50-feet, or should I trim it to 30 feet if that is all I use?
Does it matter which wires go in which slot, or it is ok as long as the same wires are matched up at each end?
Are there any tools needed other than a wire-cutter/stripper? Do I need a special crimper?
I am not an expert on this stuff but I know a little. You need a crimping tool and the arrangement of the wires is crucial and there are different solutions for different purposes. You can look up the diagrams on-line. It may be cheaper to just by the ready made cable however.
The maximum distance for GigE over cat5 cable is 100 meters, so a 50 foot length should pose no problems.
As long as the same wires go in the same slots on both ends, it will work, but there’s no reason not to follow the standard. A color diagram is usually included with the crimper, which you’ll definitely want to get if you want to get the job done in less than a month.
No, it won’t; you also have to make sure you match up the pairs–using the signal from one pair and the return from another totally destroys the benefits of pair twisting. It would be no better than using straight wires. This is probably fine for short runs at low signal speeds, but you couldn’t expect anywhere near the maximum range or bandwidth you could get otherwise.
This isn’t true. You can arbitrarily switch the pairs around, but you can’t arbitrarily switch individual wires. So for example, the spec calls for the orange pair (solid orange / orange-and-white-dashed) to be first and the brown pair to be last. You can swap these so the brown pair is first and the orange pair is last, so long as you do it on both ends, but you can’t just move one of the wires from a pair to a different position unless you want a very flaky cable. Even at 50 feet, an incorrectly wired cable will be much less resistant to interference and it’s just not worth the randomness it adds to network troubleshooting.
So you do have some freedom in the color ordering, but it’s not completely arbitrary. Think in pairs: It’s almost as simple as Aa Bb Cc Dd, except that you swap one of the wires from the middle two pairs: Aa Bc Cb Dd. If you’re wiring cables for your personal use and you wire both ends the same, that’s all you’ve got to remember.
As friedo mentions, if you’re going to the trouble, you may as well do it the standard way, and that standard you’re interested in is EIA-568-B (that’s the one that’s commonly used for regular “straight through” patch cables). Use the second color-coding column from the wiring diagram here. The way I remember it is that the striped wire comes first in each pair, the color order is orange-green-blue-brown, and you swap solid blue with solid green.
And a handy tip from someone who’s crimped an awful lot of cat 5 cables and seen it done wrong an awful lot too: don’t take off too much sheathing. The plastic part that the crimp tool pushes in should grip the sheathing for strain releif. Also, before you crimp, turn the connector sideways and look to make sure the individual wires have gone all the way to the ends of the little channels that they slide into. Also, expect to screw it up in some undetectable way (other than “it doesn’t work”) about half the time at first.
ETA: when I started writing my short story above, Q.E.D’s post wasn’t there, I swear.
Actually, it will work fine. You may experience signal loss over long distances (over 100 feet), but for shorter cables it’s fine. Not to mention, that it only matters in Ethernet and Fast Ethernet. Gigabit Ethernet is a whole different animal, and if you notice most store-bought Cat-5E and Cat-6 patch cables are made completely straight-through.
The rule of thumb, though, is to make each end of the cable, the exact same, having the RX and TX pair in the same positions on each end. Each end of the cable, should have the following sequence, from left to right:
Orange on White
White on Orange
Green on White
Blue on White
White on Blue
White on Green
Brown on White
White on Brown.
This way, your TX and RX pairs are the same wires (1, 2, 3, 6).
Some quick instructions for making the cable:
Cut off the plastic cable covering about 2 inches down from the end, so you have 2 inches worth of 8 wires coming out of the end. There should be 4 tight twists.
Unravel all the twists (be careful, so cables have a white companion to a colored wire, without any coloring on white cable. If this is the case, you’ll have to keep track of these individually).
From left to right, put this cables in the order above, holding them tightly between your index finger and thumb. For every 2 or 3 cables, bend them forcefully so that they are completely flat in your hand. By the time you’re finished, you should be holding 8 very flat wires molded in a row.
Once you have a the flat line of cables, cut off about 1.5 inches. If you bent and molded the 8 wires forcefully enough, you should still have a neat row of 8 wires, only now they’re 1/2 long.
Slide the RJ-45 over the end so that the Orange on White wire is on the left if you’re looking at the bottom of the connector (the locking tab should be on the other side). Make sure you can see the ends of each individual wire pressed up against the inside of the RJ-45 (you can see this by inspecting the front).
Holding everything tightly, crimp, and crimp tightly.
Jeez, guys. You’re going to need the crimpers anyway; just buy the ones that have the standard order written on the side. Problem solved. That way, if you ever want to cut the cable in half and make two 25 foot cables, you don’t have to pull out the magnifying glass and try and remember which order you put the wires in last time.
But there are two standard orders, aren’t they? “B” and “A”? And for some reason “B” is always listed first? These two, by the way, differ in which pins correspond to a twisted pair, so that “B” cables don’t have twisted pairs on the same pins as “A” cables.
Another thing - how in the world do people get the correct conductor into the correct hole without having a couple of inches of the sheath cut back? People tell me you just have to get practiced at it, but it looks to me like they’re sorting out the pairs and getting everything distributed correctly with just 1/4" of wires sticking out of the sheath. My cables work but they look like they’re wearing hand-me-down pants.
If you don’t want to buy tools for one cable, you can get snap connectors that require nothing but a pair of pliers to install. I use ones from Panduit, and they work really well. They also help enforce the Cat-5 standard for length of untwisted sections and such.
Basically, you just strip back the sheathing to expose the wires. You lay them on the connector bed, which has color coding to match the wires. Then you put on the top half the connector and squeeze the two halves together. You don’t even have to strip the wires. Panduit wired Cisco’s head office with these things, and they didn’t have a single failure in the bunch (several thousand connections).
One other thing - you’re using solid-core wire in an application where it isn’t suggested. Patch cables use stranded wire - this gives them flexibility and the ability to bend repeatedly without cracking the wires. Solid core wire is stiffer, and repeatedly bending it can lead to cracks and flaky cables. Solid core wire is supposed to be used inside walls and properly terminated at wall plates or patch panels, so that once installed they no longer get moved around. The cables that actually go to the computer are stranded wire patch cables. If you just run the solid core wire to the computer, then over time you could be asking for trouble if you move the cables/computer around a bit.
Is this the product? It isn’t easy navigating their web site, but the installation instructions look pretty straight-forward, although they call for a crimper.
