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rosehips
02-20-2017, 03:45 AM
Isn't it funny how you think you know how something works until you have to describe it in a story?
I get that a telegraph works by sending a series of electric pulses through a long wire, and that you use morse code. What I realized I don't understand is how you tell the message to go from point A to point B and not point C or D. Also, is it possible to send a message to more than one recipient?

Here's what I need for the story, set in a fantasy world with mixed level tech, most of which is 1910s-1930s era. There are some things that jump far ahead--it's retro-futuristic dieselpunk, so there are robots but no phones. There are telegrams.

MC has found a rebel cell and acquired important information. She needs to request help from a particular rebel (she needs the rebel to fly her somewhere) who is not at the cell where the MC is. The cell has an illegal telegraph (or something else entirely if the telegraph won't work). MC doesn't know where Rebel Pilot is, so she needs to send a message out either to several recipients at once or several times.

How would the message work? Can it be intercepted? The rebels will of course have their own code.

Thanks for helping me make sense of this!

King Neptune
02-20-2017, 04:20 AM
Facsimile machines predate telegraph, so you might use them. They were initially designed to use railroad tracks as conductors, so they will work, if you have railroads.

Nicola Tesla did the first electrical broadcasting in the 1890's, for which he got all of the necessary patents for radio, so Marconi ended up having to pay to use the technology.

And then there was semaphore, but you would need something private.

Jason
02-20-2017, 04:32 AM
Telegraphs typically in US history went between stations (think Western Union), and you would specify the recipient of the message in the header. So, if I were to send a telegraph to Alexander Graham Bell, I'd go to my Western Union here in Denver, with his name and address and give the message to the operator to send it from the Western Union in my town to the Western Union in his town.

The message would be sent over the wire, and decoded at the remote end to get the address for the recipient. A messenger would then be dispatched to deliver the message in paper form to the recipient.

Telegraphy works very similarly to the PSTN, in that there would be stations or switches connected to one another and each station would know how to open the "connection" to the remote station or switch:

http://www.history.com/topics/inventions/telegraph

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

Ironically, I was just talking about this with my folks, and aunt & uncle the other day, when someone asked when the last telegram ever was sent - the answer was just back in 2013 in India!

rosehips
02-20-2017, 05:15 AM
Thank you both.


Telegraphs typically in US history went between stations (think Western Union), and you would specify the recipient of the message in the header. So, if I were to send a telegraph to Alexander Graham Bell, I'd go to my Western Union here in Denver, with his name and address and give the message to the operator to send it from the Western Union in my town to the Western Union in his town.

The message would be sent over the wire, and decoded at the remote end to get the address for the recipient. A messenger would then be dispatched to deliver the message in paper form to the recipient.

So if Rebel A has a telegraph and rebel B has a telegraph, they could send each other messages that no one could intercept? But would there be interference from other telegraphs? Like if rebel A's telegraph is trying to send B a message, but there's another telegraph, belonging to the bad guys, in between, could they catch the message? Would they have to cut into the rebels' telegraph line, like splice it or something?

Chris P
02-20-2017, 05:38 AM
I think (but don't know for sure) that all stations on the telegraph line would be able to hear the message. Think of the old timey telephone party lines where everyone on the line could listen in (my grandparents in rural Michigan had a party line until about 1980). The non-fic children's book Kate Shelley and the Midnight Express (I know it was Kate Shelley but might not have been that exact book) mentions that the other stations on the train line heard the distress call about the bridge being out and the train plunging into the river.

From the way Jason describes it, I wonder if telegraph offices had switchboards where the sender could plug in to a dedicated line and send the message only to the recipients on that line? Seemsnlike it would be chaos otherwise.

King Neptune
02-20-2017, 06:05 AM
I believe that in different periods there were different levels of privacy in telegraph. Telex, which is what remains of telegraph is directed to a station, and it is as private as a landline phone, but that hasn't always been the case.

snafu1056
02-20-2017, 08:00 AM
Wireless technology is also a possibility for that era. Useful in warzones. And since it's fantasy you could always just invent some way to "tap" these lines or intercept the radio transmissions. Robots exist in your world, so why not some free-roaming flying robot that can serve this purpose?

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

Jason
02-20-2017, 09:24 AM
Yes, at various points in history, telegraphy in this sense of a circuit being completed, anyone that was in between sender A and B would be able to "intercept" the message insofar that they would hear the dits and dashes and then have to decode it. But then again, Morse code wasn't that complex to learn so hacking was possible.

From what I understand of the history of telephony (and believe telegraphy followed similar paths), the switchboards did have dedicated connections to various points.

So, say I wanted to send a telegram from NY to LA, I could do that by using the circuit that goes from NY to LA. It may pass through Chicago in tandem, so the operator on the Chicago switch could theoretically intercept it. But, they were busy sending and receiving their own telegrams so weren't really "listening" for stuff not destined to or from them - but it was always possible, and yes, t'was very much like a party line.

My grandparents (also in rural Michigan) would hear rings (long and short) and know the pattern for their own phone. It didn't prevent them from picking up the phone even if it wasn't meant for them and listening in, but there were also morals back then! LOL :)

frimble3
02-20-2017, 09:55 AM
What if the rebels send their messages in code? I think this was the solution for a number of big businesses sending confidential messages across the country. I saw samples of this kind of thing for financial firms for transactions. Each side has a set of code words, and can tell that when the other sends 'Once in a blue moon the eagle soars' they mean that 'temporary increase in the price of something.' Not a bizarre jumble of letters which might make the telegraphist suspicious, but something almost normal. I think regular people used a variation of this to keep the word-count, and therefore the costs, down.

MaeZe
02-20-2017, 12:05 PM
Maybe I'm misreading the posts here but I think the OP question about routing is not being answered. You can tap into a line, that much is true, but you have to intercept the message along its route.

My dad used to work at AT&T in trafficking. There are routing stations along the way that send the message down specific paths. I've seen where he worked; there were rooms of equipment that sent messages down specific phone lines (https://www.google.com/search?q=telephone+traffic+stations&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiy8473mJ7SAhVhImMKHSFLAQUQ_AUICygE&biw=1142&bih=539#tbm=isch&q=automated+telephone+exchange+equipment). Operators used to do a lot of the routing. Automation replaced the operators.

Wiki (https://en.wikipedia.org/wiki/Electrical_telegraph#Teleprinters)
By 1935, message routing was the last great barrier to full automation. Large telegraphy providers began to develop systems that used telephone-like rotary dialling to connect teletypewriters. These machines were called "Telex" (TELegraph EXchange). Telex machines first performed rotary-telephone-style pulse dialling for circuit switching, and then sent data by ITA2. This "type A" Telex routing functionally automated message routing.
The first wide-coverage Telex network was implemented in Germany during the 1930s[citation needed] as a network used to communicate within the government.
At the rate of 45.45 (0.5%) baud considered speedy at the time up to 25 telex channels could share a single long-distance telephone channel by using voice frequency telegraphy multiplexing, making telex the least expensive method of reliable long-distance communication.

In the first telegraph lines, the messages went from station to station down single lines, often following the railroad line. But eventually routing systems were developed.

Jason
02-20-2017, 07:27 PM
Hi MaeZe, I thought I had spoken to the routing part. You are correct that routing is needed to forward messages down the line. What you are calling routing stations I call switching stations because that's where a message can "switch" and be sent forward from there. Again, it's very similar to the PSTN in that you had to have people monitoring these stations to switch/route messages forward.

In telegraphy specifically, the station wasn't exactly like the switchboards of phone switchboards, but there were operators that would monitor the dedicated lines for telegrams coming in and either forward them on using a telegraph machine, or covert them to paper for local delivery.

WeaselFire
02-21-2017, 12:29 AM
Originally, telegraphs were point A to point B. To get to point C, point B received it from point A, then resent the telegraph on the second line to point C. Eventually it would get to a main office, with dozens of lines, and operators, coming in and going out. They would be received from one line, then given to the operator on the next line in the link to send out. There was no switching technology. No individual telegraph machine was addressable. Every operator in the chain could, and did, read your message. The upgrade was multiple in and out lines at a station so they could forward them quicker.

Over time, things became automated and, with the advent of telephone switching, telegraphs also went automatic. But, just like in the early days of phones, where you picked up the phone and the local operator would switch your call with wires and a switchboard to your destination. No direct dialing to begin with. Wireless communications, and eventually radio, TV and so on, worked the same way to begin with, except that every station heard every call and message within range.

Give your fantasy world the ability to contact direct station to station and you're good. Unless you need the bad guys to listen in, which is as simple as connecting two wires in between and decoding the message.

Jeff

Tsu Dho Nimh
02-21-2017, 06:31 PM
I think regular people used a variation of this to keep the word-count, and therefore the costs, down.

There were widely available commercial code books so Company A could communicate with Company B concisely. There were also private "house codes" used within a company's branches.

https://en.wikipedia.org/wiki/Commercial_code_(communications)

But some of the entries make me wonder:
From the ABC Telegraphic Code (6th edition):

ENBET Captain is insane

Tazlima
02-21-2017, 07:04 PM
Isn't it funny how you think you know how something works until you have to describe it in a story?
I get that a telegraph works by sending a series of electric pulses through a long wire, and that you use morse code. What I realized I don't understand is how you tell the message to go from point A to point B and not point C or D. Also, is it possible to send a message to more than one recipient?

Here's what I need for the story, set in a fantasy world with mixed level tech, most of which is 1910s-1930s era. There are some things that jump far ahead--it's retro-futuristic dieselpunk, so there are robots but no phones. There are telegrams.

MC has found a rebel cell and acquired important information. She needs to request help from a particular rebel (she needs the rebel to fly her somewhere) who is not at the cell where the MC is. The cell has an illegal telegraph (or something else entirely if the telegraph won't work). MC doesn't know where Rebel Pilot is, so she needs to send a message out either to several recipients at once or several times.

How would the message work? Can it be intercepted? The rebels will of course have their own code.

Thanks for helping me make sense of this!

Not sure of the nuts and bolts of telegraph operation, but the Count of Monte Cristo has a scene that involves intercepting and sabotaging a telegraph message (actually, they call it a telegraph in the translations I've read, but it sounds more like a semaphore, since the operator quips that he gets "vacation" days when it's foggy). Basically, the protagonist seeks out a low-level guy on the system, who sits in a tower in the boonies and passes along messages for crappy pay, and gives him a big fat bribe to alter the contents of a particular message.

Assuming the opposition has a way to decrypt the code itself, if your story calls for interception of the message, it should be very doable.

rosehips
02-22-2017, 02:29 AM
Thanks, everyone, you've been immensely helpful.