Is using alarm cable as Ethernet Cable safe?

Toggle sidebar Toggle sidebar
E

EmileBV

Reputable
Nov 20, 2014
27
0
4,540
Alright, so I have a weird situation here. I work at some big store and we were doing some cleaning during which I found a very long cable that I thought looked like an RJ-45 one. So I told my boss that this was probably worth some money and it was in very good condition, which resulted in him just giving it to me because it was going to be trashed otherwise.

I bought some tools and Ethernet cable ends, and then I wired the cable. During that process I found out that it had 10 wires instead of 8, which made me believe it wasn't made for internet connection. So right now this cable is hooked from my laptop to my router and the connection is flawless. However, I did some research just now and found out that this cable is in fact an alarm security one.

So I'm wondering if it's even safe to use that kind of cable for this purpose? My internet is not fast so there isn't much data going through for now. But I plan on adding a NAS to my network in the future so I want to know just how much bandwidth these cables have.

Some more info:
Current internet speed: 10MBps
Exterior color of the cable: yellow
Additional specification on it: Solar shielded, made for outdoor applications
Number of wires: 10, plus a bare-copper one and an aluminum foil all over the 10 wires to protect them I guess.
 
Solution
Solandri
The wire pairs in Ethernet are twisted as a noise-cancellation strategy. The signal is inverted and each pair carries the signal and its inverse. So one wire carries (S), the other wire carries (-S). As the signal travels over the cable, it picks up RF noise. So now you have (N+S) and (N-S). At the other end, the inverted wire is inverted again. So the (N-S) becomes (S-N). Then the two wires are added together. This gives you (S+N) + (S-N) = 2S + 0N. The noise cancels out. This is why the wire pairs are twisted - to insure they travel the exact same physical path and on average pick up the exact same noise. With straight wire, the physical paths will be slightly different and this noise cancellation trick won't entirely work...
Sort by date Sort by votes
The wire pairs in Ethernet are twisted as a noise-cancellation strategy. The signal is inverted and each pair carries the signal and its inverse. So one wire carries (S), the other wire carries (-S). As the signal travels over the cable, it picks up RF noise. So now you have (N+S) and (N-S). At the other end, the inverted wire is inverted again. So the (N-S) becomes (S-N). Then the two wires are added together. This gives you (S+N) + (S-N) = 2S + 0N. The noise cancels out. This is why the wire pairs are twisted - to insure they travel the exact same physical path and on average pick up the exact same noise. With straight wire, the physical paths will be slightly different and this noise cancellation trick won't entirely work.

The foil in the alarm wire will offer some shielding (assuming you're using a metal RJ45 jack which allows you to ground it) so you shouldn't pick up as much noise from the outside environment. But inside the foil the ethernet signals in one wire will cause noise in the other 9 (well, 7 that you'll be using). So it'll probably work for short lengths, but you'll start to get signal degradation (packet loss) at longer lengths.

So basically it'll work, just don't expect it to work as well as Cat 5e/6 the longer you make the cable. In particular, you'll have more trouble using it for 1 Gbps ethernet than with 100 Mbps ethernet. There are also some electrical characteristics like impedance which might be different, but won't really matter for short cables.
 
Upvote 0 Downvote
Solution
Alright, thanks a lot for the help but now I'm just wondering what is considered as "long distance"?

Right now the cable to connect my laptop to the router is about 18 meters long, so what if I plan on adding a NAS working at 500MBps in the future?
 
Upvote 0 Downvote


Thats about 60 feet you're probably already taking some speed hits, but it will work ok.

However IMO this is a temporary solution, to get the best speed you need the right cable as Solandri said real ethernet cable has noise cancelling properties to optimize speed. If you plan on having a NAS and want to stream and stuff from it, the correct cable is far better.
 
Upvote 0 Downvote

Ok, thanks for the quick answer, I will try to see how I can upgrade the cable in the future.
 
Upvote 0 Downvote
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom