What does it take to power a phone line? (For a Zombie Plan)

A fairly good plan, and there are multiple ways to do it that don’t rely on computers. The AP Wirephoto service was begun in 1935 with work on the basic ideas going back to Édouard Belin’s Belinograph of 1913. You need photocells and likely a fairly good phone or radio link and I don’t know how easy those would be to rustle up.

My grandfather helped/helps maintain a packet relay point on a populated island in puget sound. For a while way back when it was the most stable internet in town.

I used to install power systems for telephone switches. The most common voltage for land line was -48VDC. Depending on the system in use you could also have -24VDC and/or 140VDC, but I believe that was for long distance/toll. If I remember correctly wireless service uses +24VDC.

Thirty odd years ago, I trained as a technician for the New Zealand Post Office, which was the monopoly telephone provider. There were no electronic switches in use then. The system used step-by-step and manual switches. The supply voltage for the step by step switches was 50 volts, but what the phones used amounted to very little of that. On a manual switch (BMSB), the phones used either a feed from the switch (supply voltage 24 volts) (called common battery) or a pair of 1.5 volt batteries at the telephone set (local battery). For an article about telephone switches check Wikipedia.

50 volt DC is still used as the supply for electronic switches today.

Your friend’s Zombie Plan could use quite low voltage to supply speech battery for his phones, but he would strike a problem with the loss of volume over 150 miles of just about any kind of cable lying around today. Before fibre optic systems and microwave radio systems, there were open wire carrier systems. They used frequency division multiplexing (FDM) to allow several speech circuits over a pair of wires. A drawback for that plan, is that there are probably only a few examples around in museums somewhere.

Before those systems, there were single circuits on a pair of wires. They had no amplification, so you had to shout to be heard, very faintly, over long distances. I don’t think fax machines can do that kind of shouting.

I threw out my notes from those early years, so I don’t have the figures exact, but for long distance lines, we’re talking about 200lb/mile copper wire. As a comparison, wire for reticulating phones to a residence is about 6lb/mile.

There seem to be a reasonable number of resources on the internet for telephone related subjects, but my quick look didn’t turn up detailed information for more primitive systems such that your friend might have to use.

A possibility for sending images or plans could be HF radio fax. It’s a reasonably developed system widely used for disseminating weather forecasts to mariners. There’s also slow scan TV, where still images can be transmitted by radio. One other reply mentioned packet radio. That has possibilities if you still have the electronics (PCs, modems and so on) available.

Forget using any existing telco land lines. Line termination is tracked by several large computer systems to which will probably not be running and to which you will not have access even if they were still running. And that’s just the beginning of your problem.

That would be the TA312 field phone. You’d have to run your own land-line network, but these can be point-to-point IIRC. No faxes, unfortunately.

That packet radio looks really cool!

What about weatherfaxes/radiofaxes as mentioned above? Googling, I came across all sorts of receivers for shortwave transmitted faxes, so that you can get even grainy photos by fax from the NOAA, so vessels out in high seas can still get fancy grayscale weather pattern diagrams.

All the information I’ve seen is about receiving these offical transmissions, there’s nothing about sending anything by radio fax.

For that matter, if it’s just about sending diagrams, couldn’t he use a TV station to broadcast an image to be picked up by TV set with bunny ears 150 miles away? Heck, if it’s so doctors/engineers/technicians can walk an untrained newbie through a procedure, he could do it step-by-step on live television.

Or is that silly?

Since he wants what is already currently in use and plans on no sabotage problems, you use an alternate power supply that produces what is currently available, or use the backup generation plants for the existing system.