>Anecdotally, fence phones were still being used throughout the 1970s and perhaps even later. C.F. Eckhardt describes calling his parents who lived in rural Texas and still used a fence phone; their number was simply 37, designated on the small local network by three long rings and one short ring.

Is this perhaps an OCR or typography error? If the number were "31" that would make much more sense to encode as three long one short. A stylized 1 can look a bit like a 7 depending on how the characters are drawn.

This is amazing to see. I have some audio recordings, digitized from tapes recorded in the 1960s, of my great-grandfather who was raised on a farm in Iowa. He talks about his experiences in amateur radio in the early 1900s-1920s. He mentioned bringing telephones out into the field that could be clipped to the fence wire to make calls back to the house, which was not hooked up to an electric grid but had batteries. Sadly, he did not say how the batteries were re-charged.

The batteries were either charged using a "telephone magneto", or were taken to a local town to be charged off of mains electricity:

https://www.1900s.org.uk/1920s60s-windup-phones.htm

From what I understand, the crank was used to ring the exchange's bell, not to reload the phone battery.

The phone batteries weren't a high load kind of affair. They merely needed to change the varying resistance of the carbon microphone into an audio voltage - on the order of milliwatts of power - to send down the line. A more modern phone, still using a carbon microphone but powered by the line, needed about 20mA of loop current to do this. The telephone terms for the old system vs. the newer is "local" vs. "common" battery.

Heavy duty batteries - specifically the "A" batteries that powered the vacuum tube heaters in early radios - were made rechargeable to save cost.

This might be a bit of a tangent but I couldn't help but wonder if the appearance of 20ma here is related to the old fashioned, but I understand commonly used, 4-20ma current loop signalling in industrial applications.

> Sadly, he did not say how the batteries were re-charged.

Dry-cell batteries had to be changed, they weren't recharged.

https://www.reddit.com/r/diyelectronics/comments/y7qmhq/15v_...

If the batteries were rechargeable at all (some radio 'A' batteries [0] were), they could have been recharged by a small wind turbine [1].

[0] - https://en.wikipedia.org/wiki/Vacuum_tube_battery

[1] - https://www.wincharger.com/

Maybe they used a Delco-Light Plant

If you can get your hands on it, I recommend Other Networks: A Radical Technology Sourcebook by the same author. She covers barbed wire as well as many other ways to communicate. The book itself is gorgeous.

It's on archive.org: https://archive.org/details/emerson-lori-other-networks-a-ra...

When I was a kid, I scavenged a hunk of cable "Ma Bell" had left behind. I spliced together a quarter mile pair of wires to connect the neighbors house to mine and hooked up a battery and microphone on one side, and a speaker on the other. No luck. Then we connected the "speaker side" to the input of my friends stereo, and it was possible to be heard. I was about 10 at that time ( ~1970) and was not very aware of voltage drop. The taps and recording system I put in our basement worked much better!

If you look in vintage Sears catalogs - easily found online - I have a printed copy somewhere of the 1908 one and it's definitely in there - aftermarket phones had a bit of a "contraband" aspect to them, and were offered to be shipped in unmarked boxes. Not all local phone companies were "friendly" to people stringing up their own lines.

Some great previous HN discussions on barbed wire telephony:

https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...

There are also discussions about networking over barbed wire.

Very cool to see one comment linking to an old Sears magazine from the 1920s, showing some of the equipment people would have constructed these networks from:

https://babel.hathitrust.org/cgi/pt?id=njp.32101066805050&vi...

The thing I'm most amazed by is how "modern" the catalogue is, especially the clothing and phonograph sections.

I couple years ago I read "A Mind at Play", Soni & Goodman, a biography on Claude Shannon. He grew up on a farm and the book mentions how he made extensive use of barbed wire fence telegraph (and if I recall telephone). Perhaps one of the early experiences Shannon had regarding information.

The MIT Museum had a display (last year) of Shannon's "toys", including the famous mouse maze. I don't recall any mention of his early days using barbed wire telegraph though.

That’s really cool. I wonder if you could run anything else on a fence network. Like some sort of primitive computer network.

You could probably do AX.25 over barbed wire.

You can run Ethernet over coat hangers, barbed wire should be fine (if slow).

I was really disappointed not to see any mention of Claude Shannon running barbed wire comms in rural Northern Michigan.

As a native of Northern Illinois, I was pleased to see Joseph Glidden mentioned.

https://en.wikipedia.org/wiki/Joseph_Glidden

Edit: after reading about Claude Shannon, I too think it would have been nice if he was mentioned.

This is only vaguely related but I've been dying to drop this link after recently learning about the "Carrington Event" in 1859

The most powerful geomagnetic storm in recorded history

Likely from the largest coronal mass ejection in modern human history

The natural EMP effect was so powerful, telegraph operators were able to completely disconnect all their batteries and still communicate for hours

https://en.wikipedia.org/wiki/Carrington_Event#Telegraphs

Imagine some future event even more powerful and our dependence on all those LEO sats...

Needs more modem.