Lan using phone cable works!

greenhorn

greenhorn

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Just an FYI to those of you living in older houses. I wanted to wire my parents house for lan, but didn't want to tear up the house. I had wiring for phones, but the wire was stuck, and we couldn't replace with lan cable.

I did some googling and found out that 100 Mbps requires only 2 pairs of wires, and phone cable that we had was cat 3, which had 3 pairs. Not enough for gigabit which needed 4 pairs. Technically this wire was not rated for cat 5, but in practice you could get away with using it for short distances.
In my case it was just a few metres (ground floor to top floor) I got a couple of lan sockets, swapped out the phone sockets with them, and it worked!

I was able to get 95 Mbps on speed test which was enough!
 
Earlier in Andheri (E), a small local internet redistributor was using 2 pair wired cable for internet distribution.
Ethernet was even mentioned on the cable, totally forgot cable brand name.
 
I've used red-black electrical wire (2 pairs) for ethernet. Does it work? sure, at least for the short (few meters) that I was using it for. IIRC the ethernet spec allows for a few meters of straight cabling (without twist). Fortunately, even the red-black electrical wires are twisted pairs (but the rate of twist is different from ethernet spec, so there will be degradation, just not enough to affect the speeds appreciably).
 
I didn't take pics, there are a couple of videos online if you look. The basic principle is that only 2 pairs are needed for 100 mbps.
images (2).png

In my house, there was a red, green and blue cable + 3 white cables. This is a problem because unlike lan -ve cables, which are white + colour, cat3 has all 3 identical -ve wires. Thankfully there is a trick I learnt from telephone repairmen - I stripped and shorted red, green and two white cables and shorted red with one white, and green with the other white.
cat-3-cable.jpg

This was I was able to identify the corresponding white wire at the other end with a multimeter. The red and the correct wire will show continuity and the dmm will beep. After identifying the pairs at the other end, I hooked up red + white where orange and orange/white should go, and green+ white where green green/white should go on the wall sockets.
images (28).jpeg


Screwed everything back up, plugged one socket to an access point, laptop to another, did a speed test and got 95mbps!
 
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TEUser2K1 said:
Earlier in Andheri (E), a small local internet redistributor was using 2 pair wired cable for internet distribution.
Ethernet was even mentioned on the cable, totally forgot cable brand name.
Click to expand...
This is how the now-defunct Reliance Communications did it - at least in my location. After they abruptly shut shop more than a decade ago, they let all their cabling remain as it was, just lying around. And a couple of years later, I cut off the portion inside our place (~25 m very sturdy cable), crimped RJ45s at both ends, and use it for temporary ethernet connections to this day.

As an aside, the cable was so well-built that I used this outdoors for several years as a DIY POE carrier (12V stepped down on the other end to 5V) to power a Pi-based camera to observe a outdoor bird feeder.
 
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