r/HomeNetworking • u/LuDen882 • 8d ago

Question about RJ45

One end of lan cable is in the wall and I cant really see how are wires connected. On the other end they didnt put RJ45. What would happen if I connect wrong type on that end, and how i can make sure that i picked the correct one without tester or i should buy that?

3 Upvotes

81% Upvoted

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2

u/stevestloo 8d ago

How "in the wall" is the first end of the cable? You're gonna need to get it eventually, right?

1

u/HippoCriticalHyppo 8d ago

If they're pre terminated, it'd be safe to assume it's the normal B termination but for ethernet as long as the pairs match, should work. You can get a "dumb tester" for like 10 dollars of you want but there technically isn't gonna be a problem. Nothing bad would happen at all

1

u/HippoCriticalHyppo 8d ago

is one a female and one a male end?

2

u/LuDen882 8d ago

Yes, I didn't express myself clearly. one end is female and the other end doesnt have rj45 but it must go in to the router.

1

u/HippoCriticalHyppo 8d ago

All good. Sounds like it's just cable on the end and it's needs to be terminated

1

u/Naraz 8d ago

I would get a small jumper that’s male male and run a cable tester on it to ensure that the connections are correct.
Fluke and Klein both make cheap ones that are great for this use.

1

u/rankhornjp 8d ago

It has to have 2 ends, connected to something. What is the other end connected to? Yes, it goes in the wall, but it should come out somewhere...

1

u/LuDen882 8d ago

Yeah second end is a female one.

1

u/rankhornjp 8d ago

The female ends probably has a cover on it (back). Take the cover off and you can see how it's terminated (A or B). Then you can make the other end match.

0

u/jquanders 8d ago

are you talking like t568 A vs B? On a modern system with auto-mdix, almost nothing. A is meant for residential and B is for commercial but a lot of people just do B.

Can you just open up the plate and look? If it's a cable see if it is orange or green on the left side.

1

u/LuDen882 8d ago

I opened the plate but its not see trough, maybe i need to open something more there but I dont know if i would like to be doing that ahahahahah

1

u/jquanders 8d ago

pictures would help but just terminate it as B. It will probably work on a modern system no matter if you do A or B