As a field service technician, I regularly need to connect to things having an RJ45 connector; PLC, HMI, and other network equipment.

I've previously used a long RJ45 cable, wound it up around my arm then tried to keep it tangle-free in the van until next time I needed it. If you're in the same trade you'll probably know the frustration this leads to - always a problem as you have to unravel the thing then find the ends etc...

I thought about buying a commercial wind-up RJ45 cable reel, but they cost around £80 - not for me, thank you!

This is a bit of a compromise, but it seems to be working so far, and saved a lot of hassle as you can unwind just as much as you need in each situation.

Please let me know if you have any ideas or improvement suggestions, thanks for visiting :-)

Apologies for the vague descriptions and lack of photos - I hadn't decided to publish this when making it so have missed out photos of a few steps.

Supplies

A second-hand telephone extension reel (can be new if you can't find second hand, but there's a lot around these days as people are moving away from landline phones)

An 8-meter (longer or shorter depending on your requirements and the drum you're going to use) FLAT profile network cable - Amazon or eBay as required

Small files, screwdriver, pad saw/coping saw (thin-bladed saw)

Small cable tie(s)

Some elbow grease (optional)

Step 1: Empty Out the Cable Reel...

You'll need to take apart the cable reel and remove the existing cable. As this would be different depending on the cable drum, I haven't given specific instructions.

Mine was screwed together and quite easy to take apart. Make sure you don't lose any of the screws or get them mixed up if they're similar sizes!

Step 2: Decide the Best Way to Fit the New Cable

The original cable was looped through these three holes to provide strain relief.

I decided that I only need to enlarge one of the holes to put the new cable through, then fix it with a cable tie to prevent movement. If you don't fix it, you may find that it pulls out during use and the loose end disappears inside!

Leave enough free cable on the centre of the drum to reach your laptop when the drum is resting on the table next to it - about 12 inches (30cm) should be sufficient.

Step 3: Enlarge Exit Hole and Refit Cover

As the RJ45 plug was almost the same size as the British Telecom socket which was originally on the reel, I only needed to file out a groove for the strain relief to pass through. This will vary depending on the reel you decide to use.

The blue clip on the outside was my first attempt to keep the loose end out the way when winding the drum. After taking the photos I removed the clip and now just push the loose end of the cable back into the centre of the drum before winding the rest - again, this is down to preference...

Step 4: Over-wind Protection Device!

My cable drum had a two-part plastic ball on the end which stopped the cable from being would fully into the drum. I was able to split it apart with a screwdriver and file out the centre to fit over the new cable.

The point of this is to stop the end from disappearing inside the drum when you're winding it!