How to tell cable is Cat 5?

I bought one of these cables - link as i want to move my router away from the wall socket so i can maintain a wired ethernet connection to a few of my devices.

Amazon claim this cable is Cat5, and ive emailed the company who said its also Cat 5. However when it arrived it has no marking on the cable jacket, and the only mention of anything related is its "twisted pair".

Would you assume this is Cat 5 before i go running the cable?

Edited by bobble_bob (Tue 27-Aug-24 15:03:39)

That is not a cat 5 cable, it is a modem cable. What is your incoming internet? Is it FTTP or FTTC?

This cable is no good whatsoever for FTTP, but should do you for FTTC.

Its FTTC yea. Ive used RJ11 cables before to extend the location of the router, and they have Cat 5 printed on the cable as they conform to Cat 5 standards

My understanding was Cat 5 isnt a cable in itself, its just any cable that conforms to Cat 5 standards - namely twisted pair

Edited by bobble_bob (Tue 27-Aug-24 18:26:37)

If this is just from your wall socket to your router for ADSL or FTTC, then it doesn't need to be Cat5. It only needs to be telephone cable, which is Cat3, and it only uses a single pair.

Cat5 is a standard defining what frequencies it can work with, attenuation etc. The frequencies used by ADSL and FTTC are lower than those for ethernet. (G.Fast uses higher frequencies, which is one reason it has such a low range and poor reliability over telephone cabling)

Cat5 with 2 pairs can do 100M ethernet over 100 metres. Cat5e does 1G and 2.5G ethernet over 100 metres, and uses 4 pairs. Ethernet uses RJ45 connectors, with 8 pins. Your ADSL cable has an RJ11 connector, most likely with 4 pins in a 6 pin housing, and cannot be used for ethernet.

The copper cabling from the cabinet to your house is quite probably hundreds of metres already, so an extra 10m of Cat3 isn't going to make much difference. Bridge taps do though: that's where the cable enters your property and then splits in multiple directions to different extension sockets. Disconnecting such extension wiring *can* make a noticeable difference to speed.

Edited by candlerb (Tue 27-Aug-24 20:14:17)

Cat5 as I understand it is 8 core. Your cable is 6 core [of which just 2 cores are used], so the question is really whether it is cat5 equivalent. It shouldn't be marked as cat5, because it isn't.

But this is probably one of those cases where you have to be pragmatic. FTTC only goes to 80 Mbit/s, so the full cat5 capability is not required. I am fussy about my cables, but in this case I would just be comparing modem/router stats before and after. Depending on the length of the new cable, I would accept a little bit of degradation. How long is it?

Also, you don't need to run it to test it. Just lay it on the floor in a big loop and try it.

Its only 10 metres. I have existing ethernet running for the wired devices, so rather than install a longer ethernet cable, seems easier just to move the router a few metres

Edited by bobble_bob (Tue 27-Aug-24 20:33:33)

Given the choice between extending a modem cable and extending ethernet, I would extend the ethernet. For the distances within a house extending ethernet will never lose performance, whereas extending the modem cable will.

To your problem, it is not worth the effort to argue on whether the modem cable is cat5. Just do a before and after line stats with the cable. Either the reduction in performance is big enough to bother you or it isn't. If it bothers you, extend the ethernet instead.

Post deleted by MHC

That is expensive ...

I always went for Kenable supplied cables to connect socket to modem, decent quality and suitable standard.. Their 10m cable is one third of the price:

https://www.kenable.co.uk/en/computer-cables-/other-...

A full rangel of lengths and black or white.

Thanks for that, i have heard of them before but never used them

i use Rhino cables these days, either direct or from Amazon.

https://rhinocables.co.uk/rj11%2Dto%2Drj11%2Dadsl%2D...

Have used them for years for things such as that. In almost every case, they have improved the connection speed by a noticable amount - and cheap so I always had a couple spare.

They also have an ebay store with free/included delivery: https://www.ebay.co.uk/itm/195523548610?_nkw=adsl2+h...

Edited by MHC (Wed 28-Aug-24 12:50:10)

HII ,
Check the Jacket: Look for "Cat 5" or "Category 5" printed on the outer jacket of the cable.
Inspect the Wire: Cat 5 cables have four twisted pairs of wires inside.
Use a Tester: Verify with a network cable tester that supports Cat 5https://19216801.pro/.

In reply to a post by romilly:

... Inspect the Wire: Cat 5 cables have four twisted pairs of wires inside.

We know it won't have 4 pairs. It's a modem cable with RJ11's.