David Freer's story in the Ring of Fire anthology "Lineman for the Country" described the beginnings of wired telecommunications in the 1632 universe and the founding of AT&L. Like any good story, much of the technology was mentioned, but not described in detail. This article seeks to fill in the gaps in that story, and provide a glimpse into the development of non-radio telecommunications in the USE. This article will not attempt to go into the details of the history of various types of telecom. Please see the references at the end for such history.
You have used a telegraph. You don't know that, but it's true. Have you ever stood inside your house and flicked the lights on and off to signal to someone in the driveway? Have you ever pressed a doorbell and had a bell inside the house go Ding? You, my friend, have used a telegraph! At its base, a telegraph is nothing more than a doorbell. Press a button here, and something makes a sound "over there." The very first telegraph, made by the famous American scientist Joseph Henry, used a switch and an electromagnet to move an iron bar and ring a bell.
I just can't write an article about the telegraph without a physics lesson. How does that doorbell ring? The answer took the work of half a century by scientists on two continents. Electricity running through a wire produces a magnetic field. (And vice versa but let's stay focused here.) If you take a flashlight battery, and hook a long piece of wire to it running up and down, a magnetic compass brought near the wire is deflected from north. Sadly, the compass wiggles slowly and only a little, even if you use a lot of electricity. It certainly won't ring a bell. What did Henry do? He took the wire, covered it with silk so that it did not short out against itself, and wrapped it round and round a horseshoe. As the electricity wrapped around in a circle over and over and over, each bit of wire added its bit of magnetism, and together they did what one small length of wire could not do. More wire allowed more loops and generated more magnetism.
By making up a "code," we can send complex messages using this system. The simplest code is just to count letters. You can do this with a doorbell. One ding indicates a step along the alphabet. So, the message "abc" would be sent ding, ding-ding, ding-ding-ding.
This simple code is very inconvenient. Sending a "Z" requires pressing the doorbell button twenty-six times. Samuel Morse and others came up with a number of clever ways to make the process shorter. The most important was making the system make a sound both when you PRESS the doorbell button AND when you let it go. Ding-DONG or more accurately for Morse's sounder: Click-CLACK. This lets you distinguish long and short presses, and you can make a much better code. (Morse code for "Z" is --.. )
There are several variants on "Morse" code. Two of them are known to be used in Grantville: "International" Morse used by the Ham radio operators, and "Railroad" Morse used by the operators for AT&L. The two codes are slightly different, but many operators are comfortable in either.
So, we have a wire, we have a doorbell button, we have the new weird doorbell that goes click-CLACK, we have a code . . . DONE! Not hardly. What else do we need to make a commercial telegraph operation?
First, we need wire. Modern telephone and electrical wire is copper, but copper wire alone is weak, and requires too many telegraph poles. The transcontinental telegraph in the US used #8 iron wire at 375 pounds per mile. Sometime after the civil war, the telegraph companies switched to copper-clad iron wire, then to multistranded copper over a steel weight-bearing core. No one in seventeenth-century Europe will be making that any time soon. It's iron for us.
The problem is, iron wire placed up on poles in the air rusts; #8 iron wire hung out by itself alone in typical North American weather rusts through in a year. The solution in the 1860s, and for the USE is to "galvanize" the wire, that is, to coat it with zinc. For every mile of wire, we will need ten pounds of zinc.
This raises another problem. We can't just lay the wire on the ground. We need poles. Iron wire needs the support of twenty two poles per mile. That's a theoretical number, incidentally. In practice, allowing for the effects of terrain, you have to figure that 40 miles needs approximately 1000 poles and 135 miles needs 3500 poles.
The use of fewer poles results in the wire sagging, and if multiple wires are strung from each pole it becomes possible for the wires to touch when swaying in the wind. Live trees make poor telegraph poles for several reasons. They grow, and the wires get pulled, they have leaves and other branches that can short out the wires, and they have sap running through them that acts as a conductor, helping "earth" the signal. Additionally, frequently there's no strong tree where you want one. It's far better to have poles made from dead trees that don't have sap, don't grow, and lack branches. Don't lose count. We need twenty two per mile.
There is another complication. You can't just hang the wire from the pole itself. We need insulators. Wire simply stapled to the pole will work over very short distances (a few miles) when the pole is utterly dry, and the weather is fair. However, the least hint of dew, or moisture or rain, and the wire is "earthed" or shorted to ground. No signal can get through when the water running down the pole carries the electricity into the ground. Insulators prevent the electricity in the wire from reaching the ground.
This photo, of a telephone line in western Kansas, shows a Hemingray-17 insulator supporting a galvanized iron wire held on by a loop and wrap of galvanized wire. This is the "standard" installation of a glass or porcelain insulator. Note the design of the insulator. There is a groove near the top, which supports the wire, and then there is a VERY long path down the outside of the insulator, around a "petticoat" or "skirt" and then back up INSIDE the insulator before it finally touches wood. Glass insulators get their surfaces dirty. Soot from town fires or passing trains is particularly conductive. Insulators crack and water settles into the cracks, and so on. With this skirted cup design there is a long path for any electricity to reach the wood, and in all but the hardest storms, the inside of the insulator is dry and provides a poor path for electricity. Conductive dust and soot wash off glass insulators easily in the rain. The most common modern insulators are porcelain. Porcelain attracts water less than glass, but it is harder to make, and must be vitrified entirely through. Glazed ceramic insulators absorb water if the glaze cracks in the least bit and then fail as insulators.
Good insulators are critical to telegraph (and telephone) operation. Without insulators, maximum signal distances are a few miles and only that in good weather. Fortunately, making insulators is not all that difficult. Even "threaded" insulators which "screw" on to the support rod that holds them can be made by apprentice glassmakers with little training. A few samples should suffice to allow any glass shop to make adequate insulators. The Hemingray 16 shown below is a good example of an advanced design that is simple to cast. It incorporates advanced features such as internal threads, "drip points" and a fluted skirt lip.
At this point, someone usually asks, "Why do we need insulators like that at all? Why not just use insulated wire?" Of course, today we do. If you look at modern telephone lines in most places, the insulators are disappearing as the bare wires are replaced with Teflon and other plastic-coated lines held off their poles with plastic spacers. I hope that I do not need to go into why Grantville will not be making Teflon coated wire or fiberglass for several years.
Second, we need batteries. Wait, it's not second any more is it? Oh well, fourth then. We need batteries. Yes, of course, as long as our main telegraph office is in Grantville, we can power the telegraph from the power lines. But even in the twenty-first century, that's not really done. Up-time telephones are run from batteries that are charged from the power lines. Downtime, unless you're in Grantville, you don't have power lines to charge your batteries from, and you must use 'primary' batteries that, like the batteries you buy at the drugstore, make electricity due to their chemistry, rather than being charged.