this post was submitted on 22 Jul 2025
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Are CAT6 RJ45s supposed to be physically different from their CAT5 counterparts? I've bought some CAT6 RJ45s to match my cables and feel like I'm hallucinating because they don't fit into the Ethernet port. I've looked around in local tech stores, bought online and see all the CAT6 RJ45s are the same everywhere else, but when I use a CAT5 RJ45 it actually fits into the Ethernet port in literally anywhere. Crimping is suddenly exponentially harder with CAT6 RJ45s too for some reason too and after years of practicing crimping I feel like it's a skill issue at this point. I even searched up just to be sure but while answers say they're the same my eyes and fingers are feeling the difference. What's going on? What am I doing wrong? I'm now doubting whether CAT6 RJ45s are even supposed to fit in my Ethernet ports at home.

Update: The answer really was the crimper all along... until I get a CAT6 crimper I guess I'll just crimp harder for now - now everything fits, 1 year and 2000 jacks later, how embarrassing...

Thanks very much, everyone!

Post-update: So the cable worked at 3am... only to crap out at 10am - apparently both my test cables are bad in the same wires (3-6) because as the ISP service guy says, "it could've broken on the inside since the shielding's so soft". They rewired everything and now everything's fine, I guess...

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[–] kuroshido@ani.social 14 points 1 week ago (2 children)

Cat6 jacks are slightly different in their layout and crimping.

They’re 100% compatible with all your existing ports, however they do require a cat6 compatible crimper which crimps slightly deeper than on cat5.

So likely you’re having trouble because the pins are not deep enough and are preventing the jack from being insertable.

[–] glimse@lemmy.world 7 points 1 week ago (1 children)

I know this is pedantic but it's worth noting that CAT6 caps often have bigger "channels" to accommodate the large gauge wire. If you use a CAT6 cap on a CAT5 wire, it's possible to miss the copper with the spike. It's happened to me more than once - though I've crimped literally thousands of wires

[–] SidewaysHighways@lemmy.world 2 points 1 week ago (1 children)

I've had networks absolutely fail entirely, shortly after putting in a cat5 cable crimped into a cat6 termination on the switch.

cut it off and tried again(all we had onsite that day) and it worked. ¯_(ツ)_/¯

[–] glimse@lemmy.world 2 points 1 week ago

Yeah, you can usually get away with it if you're careful and test but even then, bending it wrong can diminish a connection.r I only carried CAT6 caps in my bag so if I ever had to tip a CAT5, I'd put some force into trying to pull the wire out and then test it.

Testing (like with a tester lol) is mandatory because plenty of devices still kinda work with 4 bad wires and you might not notice. Had a client with a gigabit connection but awful speeds....turns out it was a poorly crimped wire from the modem to router!

[–] velummortis@lemmy.dbzer0.com 5 points 1 week ago

This is something I didn't know, I just used the crimper that came with my networking kit...

[–] LifeInMultipleChoice@lemmy.world 5 points 1 week ago* (last edited 1 week ago) (1 children)

Maybe is just preference but if you ever get the chance, try one of the pass through crimpers. They are like making cables on easy mode. The number of failed connections usually plummets and costs only go up by a few cents. (May be priced the same now).

If you haven't used one before essentially you push all the cables through the end, and then it crimps/cuts at the same time, so none of the individual cables can accidentally be not fully in.

Id look somewhere other than Amazon for one but this will give you an idea that you can find one for cheap, you don't have to get a $100 tool.

https://www.amazon.com/dp/B07YC9TQKH?psc=1

[–] SidewaysHighways@lemmy.world 2 points 1 week ago (1 children)

those in the low voltage biz absolutely abhor the use of the EZ terminations.

many many hours of getting yelled at by clients because their cameras or WAPs aren't working right

less of an issue of it's not a POE device, but once you get used to the muscle memory of terminating a cat cable, the EZs are more trouble than they're worth.

[–] LifeInMultipleChoice@lemmy.world 2 points 1 week ago (1 children)

That's the first I've heard this, we wired a hole building with them after Hurricane Michael. So all our cameras were POE. I wonder how we didn't have the same issues? Any idea what causes an issue

[–] SidewaysHighways@lemmy.world 2 points 1 week ago (1 children)

usually because people leave too much hanging out the other side and eventually it will short.

but on cameras and other stuff outside, moisture will get in and corrode. i mean that still happens with regular terminations, but they can usually last 5+ years if properly shielded from the elements. EZs will fail after a year or so

[–] LifeInMultipleChoice@lemmy.world 2 points 1 week ago* (last edited 1 week ago)

The way they cut I didn't think they'd be able to short. The moisture thing makes sense if they are outdoors though. I would have figured it'd be hard to get water in the port without the camera going bad as well. I'll have to keep an eye out for that. Thanks for the tip!

[–] couch1potato@lemmy.dbzer0.com 5 points 1 week ago

Fun fact; you can absolutely crimp RJ45s with a razor knife. Carefully push down each pin one at a time with the blade. I've both done this when I couldn't find my crimper, and to troubleshoot/fix cables where an open was found.

[–] slazer2au@lemmy.world 2 points 1 week ago (1 children)

Going to need pics of what you are doing.

Some cat6 cable will have a plastic cross section you need to remove to get it into the RJ45 plug.

[–] velummortis@lemmy.dbzer0.com 3 points 1 week ago

Sorry this took so long, here you go! CAT6 on the left, CAT5 on the right

[–] LazerDickMcCheese@sh.itjust.works 2 points 1 week ago (1 children)

They should be fitting...can I get a visual for what you're talking about?

[–] velummortis@lemmy.dbzer0.com 2 points 1 week ago (1 children)

Sorry this took so long, apparently nobody likes an HEIC...

The CAT6 I crimped is on the left, the CAT5 is the ISP's work.

[–] PancakesCantKillMe@lemmy.world 4 points 1 week ago (1 children)

Side note on Apple’s heic images. You are right, they are difficult to manage. I took a holiday and discovered all my images (1500-2000) were orphaned on my phone by Windows. After learning why, I refused to pay MS the $1 for the codec. As it turns out, Linux can handle them with some tools. A small script converted them all to jpg and that was that. I’ve since changed the setting on my phone to jpg. Heic is a pain in the butt to me and isn’t worth whatever gains claimed. Linux can help, but newer versions of the phone OS require newer versions of the heic/heif toolsets since the format is still evolving. Apparently. JPEGs it is then.

[–] velummortis@lemmy.dbzer0.com 3 points 1 week ago

That $1 is diabolical, especially when there was a separate MS Store link giving it for free anyways... I don't even know why I enabled the HEIC storage, no app will accept it when I upload (used GIMP to export JPG) - disabling!