Buy or Make Ethernets

Do you guys find it better to make your own length ethernets or buy premade ones of vary length? Like especially on the robot to connect radio to rio, what do you guys think.

EDIT: And also, if someone doesn’t mind explaining difference between like CAT5 and CAT6 and the different connectors and which is best for FRC, that would also be helpful.

We have a kit for crimping custom length ethernet connectors which helps keep our wiring nice and neat. IIRC the only things you need for it are a large spool of ethernet wire, the end housings, and the crimping tool. An ethernet tester is also very useful for diagnosing ethernet wire problems.

I’ve made my own before, it comes in handy when wiring up your house (back when wired was noticeably faster). But, when it comes to the robot… I would rather use a pre-made cable. It’s more reliable, easier, and quicker. And you have plenty of room to coil up any excess!


You are correct. That said, if you don’t use a tester, you are asking for trouble!

In addition, you want to make sure you are following color code standards. CAT5/CAT6 have multiple pairs in them, each with specific twist rates. Mixing wires from different pairs will degrade performance.

Recommend a source for this stuff?

You are better buying unless you do it as part of your job. I can do it, I have the tools, but I can guarantee that my crimps are not as high quality as the cheapest cable you can buy. Also, if you make your own, you’re almost certain to be using solid core wire, and you’re better off using stranded in a high vibration environment like a robot.

Comes in varying lengths and colors and it’s cheap.


I bought stuff to make my own cables for my apartment, and we ended up using it on our robot this year. Hardest part was getting the strands in the correct order. Here is what I bought:
Cat 5e cable:



Strain Relief Boots:

We used this wiring diagram:

1 Like

when it comes to the robot… I would rather use a pre-made cable. It’s more reliable, easier, and quicker.


Look at monoprice for cheap Ethernet Cables. You spend $5000 to $6000 to play matches, why take a risk trying to save $5 on an Ethernet cable?


I say buy - simply cause you asked that question. A bad cable can hurt your team and there is a lot to know. CAT nn specifies how fast the cable can go(10/100/100o mbps etc) and also what connector and wireing sheme and the min and max length of the cable etc etc. (there is a reason the shortest cable you usually can buy is 3feet). So unless you want to learn all this stuff and get really good at it - buy the cable. If your hub/radio/device says CAT 5 get a CAT 5 etc. Even though Cat 6 will work in place of a cat 5 its extra cost is wasted as it wont benefit you as the device has a cat 5 port and never use a CAT (lower) for a CAT (higher) scenario

3468 just bought a pack of 6" Cables to connect to the Radio PoE Injector.

Then for working on the robot tethered, usually just at competition, we bought one of these reels.

We had issues with every single custom made cable we had this year. It really takes some skill to do it right. We swapped out for bought cables this year, but may revisit making cables again in the future.

1 Like

We buy. They’re very cheap from sites like Monoprice and we buy lengths ranging from 6”, 1 foot, 1.5 foot, etc. all the way up to a 50 foot length for tethering at the practice fields. Ours are even all purple to go with our branding!

That said we do have the crimping tool and all the parts needed to make our own, so when one of the RJ45 “tails” snaps off, we can cut off the entire end and repair it.

That’s because the bulk cable you usually find locally is for fixed plant use, not patch cords?

I also installed ethernet cable in our house many years ago, I have the crimper and some extra ends, and the color code…and I still would rather buy patch cords for the robot.

Your data control centers at some major industrial plants and utilities are built on Monoprice Ethernet cables. If it’s good enough to run the country it’s good enough to run your robot.

I like to make but then I would make every type of wire if I could. It gives the wiring kids new skills to learn and helps to keep the robot neater and lighter. Though as others said I wouldn’t recommend without a tester (a multimeter can work in a pinch but it’s a pain to use).

Yes in our plant we do our own ends for medium runs. We use fiber for longer runs. If it shorter than 30 ft, we buy a patch cord. Cheaper than the labor to terminate the ends. Most likely done with a better crimper by a guy who does it all day ever day. You generally get a good crimp with a manual crimper if you know what you doing. It is a tedious job. I rather pay somebody else. YPMV (your plant may vary) :slight_smile:

The students on my teams have asked me this question every year, and every year I tell them this. I only own two crimpers - (1) Anderson PowerPole Crimpers, and (2) Terminal crimpers. Everything else I feel are either not worth my time, or well worth the price I’m paying to not be screwed up by me. Ethernet cables are a prime example - a failed ethernet cable is a failed match, and nobody wants a failed match. It’s just not worth it; I don’t care how many ethernet cables you think you’ve done or how good you think you are, unless you’re a professional ethernet cable maker (and have made thousands of perfect cables) then I don’t even want to talk about it, because even a professional ethernet cable person will tell you they’re not fool-proof and to just buy one a machine made.

I had one kid who claimed he made hundreds of cables, and he made a custom-length cable from the one I had on the robot without me knowing “because it looked better on the robot.” We got through to quarterfinals, when we started having radio problems. I looked at the robot, and noticed the connector on the ethernet cable was different. We borrowed a tester from another team, and sure enough something was wrong with the cable. He whipped out his crimper and another connector, and I whipped out my pocket knife and cut the cable in half, and yelled, “that’s why we don’t make our own ethernet cables!” Some people don’t learn from their mistakes, but I wasn’t in the mood to let him repeat it.

Oh, and CAT5e/CAT6 doesn’t really matter in FRC. We’re not dealing with gigabit networks on our robots (in most cases) and don’t need to worry about the nuances.

Jersey cares a lot about how our cables look, thus we will buy yellow CAT5e cable then crimp our own. This is purely for ascetics. After we crimp them, we always use a cheap Rj45 tester.

Yeah I didn’t mention it in my previous post but it’s worth bringing up - the professionally made cables can be purchased for ridiculously cheap like a buck or two or three. That’s just not worth my time to piece together the parts and line up the wires and crimp them and then test and fix any issues.

LOL! One source of our robot problems early on was that we were building our own ethernet lines. Do not suggest that option.