A quiet shift over the last couple of decades in many places has been the disappearance of the traditional copper phone line. First the corded landline phone was replaced by cordless, then the phone migrated to a mobile device, and finally DSL connections are being supplanted by fiber. This leaves copper-era infrastructure in houses, which [TheHFTguy] decided to use for Ethernet.
The hack here isn’t that he bought some specialized network boxes from Germany, though knowing they exist is useful. Instead it comes in his suggestion that they use the same technology as mains networking. Mains network plugs are a dime a dozen, but noisy power lines can make them of limited use. Our hacking curiosity is whetted by the question of whether a cheap mains networking plug can have its networking — in reality a set of RF subcarriers — separated from its mains power supply, and persuaded to do the same job at a fraction of the cost. Come on commenters – has anyone ever tried this?
This brings back memories. Around 1989 I had a PhoneNet network (AppleTalk via phone line) to link two computers and a printer, piggybacking onto the existing phone wiring. Only 7 orders of magnitude slower than gigabit Ethernet.
Funny, I did exactly this at home also with PoE to distribute my WiFi. Everywhere we had a landline phone back in the day, we now have an access point. :D
Also, when our neighbor got a solar plant that needed a network, we moved the router into the basement and used the now unused landline to get Ethernet upstairs.
oh haha from the headline i thought we were using it as an alternative to mains power. I just checked and mine is dead now but for years after it was disconnected, they still applied some voltage to it. I always assumed it would be enough to light an LED at least.
I used to work in telecom; that’s a regulatory requirement. Even with no service subscription, you could still hook up a phone and dial 911.
It should stay that way…for backups
All meth-heads climbing poles put behind bars
I tore out my old home intercom (Everyone has phones now), and wondered what to do with the free 24AWG cat-3 wiring. Initial testing showed it could carry 100BASE-TX without excessive errors, and could even do mode-A PoE. The amperage 802.3af carries is barely enough for a RPi zero, but if you had a local battery reserve to handle the peaks, it should work.
There’s only 3 pair in cat-3 cabling, so no GbE and no mode-B/4P PoE is possible, but limiting the ethernet and power to 2-pair means you could supplement it with RS-422 or RS-485 on the unused pair.
There’s also the possibility of carrying up to three distinct 10BASE-T1S signals with PoDL per cable, but I expect that increases the equipment costs significantly.
Standard CAT3 is 4 pair. You may have something else.
Maybe 4 pair is standard in some contexts, but 2 pair and 3 pair is very common in house wiring (in North America anyway). The cat3 spec doesn’t require 4; pretty sure even the 25-pair telco cables were technically “cat3”.
I’ve used coax to networking adapters for years to support a long distance run in a building. only 10Mbps, but for what it was running it was plenty of bandwidth. Could also run HD-SDI on the cabling.
I wonder how far you could get with 100Base-T1 and 1000Base-T1 over telephone wires. While devices are still expensive, the PHYs can be bought for less than $10 a piece.
Please don’t encourage this nonsense. Our RF noise floor is already ridiculous, and powerline networking is one of the biggest pollutants.
And then there are houses that don’t have phone wiring anymore and people try to run a landline over coax because the cable TV wiring is unused.
I built my house in 1993, and installed two runs of CAT3 to each room, terminated on “66 blocks” in the basement.
It works fine, no errors, for GigE to this day due to the short length of the runs.
A) Some HaD(!) tags that can help: homeplug av, power line communication, G.hn
B) pretty sure there was a HaD article many years ago where someone just modded their HomePlug AV adapters to run over whatever he wanted: Just disconnect the inject-RF-into-mains part (capacitive coupling I think) and connect it to whatever you want. Possibly even with powering one of the HP-AV devices over the cable via DC???
Can’t find that article.
C) You can also by basically a pair of ADSL modem and DSLAM and run your own local in-home DSL connection.
That’s how they did fiber internet around here. Fiber to the unused phone distribution box, then connecting to the old phone wiring going into the house. From what I understand, this is using G.fast, which is related to DSL.
Like with power line, the downside is RF noise. In my place, the noise floor in the VHF band raises by about 10dB when them modem is connected.
Ma Bell installed multiple varieties of station cables. The house I grew up in (built 1952) had “telephone twist”, 4 conductors color coded as green/red/yellow/black, with all 4 wires twisted together and a jacket overall. The green/red wires were used as a pair to deliver POTS service, the black/yellow could be used for a 2nd line or to deliver 6VAC for the incandescent lamp in a Princess or Trimline phone. Because the wires are twisted as a group and not as individual pairs, I doubt that you could get any sort of usable Ethernet connection over this type of cable.
Later installations used 3-pair station cable, color coded white/blue white/orange white/green, with each pair twisted separately within the jacket. You might get a usable-in-a-pinch network connection over this, since 10/100baseT only needs 2 pair, if-and-only-if the station cables are home runs (each running separately to the demarc), not daisy-chained from one jack to the next, no branches (aka half-taps).
My present house (circa 1970) has 6-pair station cable, daisy-chained. I’ve never tried to use it for anything but POTS.
Later installations used 4-pair Cat3 cable, which I have seen pass 100baseT over a shortish run. YMMV.
I am getting 1Gb/s over the cat5 I ran 26 years ago, but the runs are short (10s of feet).
Additional thoughts:
If there are not 4 pairs to support PoE, you could power the phone from a wallwart or PoE injector.
Some IP phones can communicate over WiFI, so you may not need cabling at all, just a wallwart and a WAP.
That all being said, you might look into https://www.nvtphybridge.com/products/#polrefamily or https://www.mitel.com/products/phybridge-polre if you must use existing cat3 cable. (PoLRE stands for Power over Long Reach Ethernet)
The jack pictured is ugly, with a capital UGH. You should never try to double-punch 2 wires into a single 66 or 110 contact; it is unreliable.
Wouldn’t there be a problem if someone dialed the phone number?
“First the corded landline phone was replaced by cordless” that’s like saying… well, it’s just wrong. A cordless phone is still a corded landline.