Only then do you pick up a calling-cord from a shelf at the base of the switchboard. This is a long elastic cord mounted on a kind of reel so that it will zip back in when you unplug it. There are a lot of cords down there, and when a bunch of them are out at once they look like a nest of snakes. Some of the girls think there are bugs living in those cable-holes. They're called "cable mites" and are supposed to bite your hands and give you rashes. You don't believe this, yourself.

Gripping the head of your calling-cord, you slip the tip of it deftly into the sleeve of the jack for the called person. Not all the way in, though. You just touch it. If you hear a clicking sound, that means the line is busy and you can't put the call through. If the line is busy, you have to stick the calling-cord into a "busy-tone jack," which will give the guy a busy-tone. This way you don't have to talk to him yourself and absorb his natural human frustration.

But the line isn't busy. So you pop the cord all the way in. Relay circuits in your board make the distant phone ring, and if somebody picks it up off the hook, then a phone conversation starts. You can hear this conversation on your answering cord, until you unplug it. In fact you could listen to the whole conversation if you wanted, but this is sternly frowned upon by management, and frankly, when you've overheard one, you've pretty much heard 'em all.

You can tell how long the conversation lasts by the glow of the calling-cord's lamp, down on the calling-cord's shelf. When it's over, you unplug and the calling-cord zips back into place.

Having done this stuff a few hundred thousand times, you become quite good at it. In fact you're plugging, and connecting, and disconnecting, ten, twenty, forty cords at a time. It's a manual handicraft, really, quite satisfying in a way, rather like weaving on an upright loom.

Should a long-distance call come up, it would be different, but not all that different. Instead of connecting the call through your own local switchboard, you have to go up the hierarchy, onto the long-distance lines, known as "trunklines." Depending on how far the call goes, it may have to work its way through a whole series of operators, which can take quite a while. The caller doesn't wait on the line while this complex process is negotiated across the country by the gaggle of operators. Instead, the caller hangs up, and you call him back yourself when the call has finally worked its way through.

After four or five years of this work, you get married, and you have to quit your job, this being the natural order of womanhood in the American 1920s. The phone company has to train somebody else -- maybe two people, since the phone system has grown somewhat in the meantime. And this costs money.

In fact, to use any kind of human being as a switching system is a very expensive proposition. Eight thousand Leticia Luthors would be bad enough, but a quarter of a million of them is a military-scale proposition and makes drastic measures in automation financially worthwhile.

Although the phone system continues to grow today, the number of human beings employed by telcos has been dropping steadily for years. Phone "operators" now deal with nothing but unusual contingencies, all routine operations having been shrugged off onto machines. Consequently, telephone operators are considerably less machine-like nowadays, and have been known to have accents and actual character in their voices. When you reach a human operator today, the operators are rather more "human" than they were in Leticia's day -- but on the other hand, human beings in the phone system are much harder to reach in the first place.

Over the first half of the twentieth century, "electromechanical" switching systems of growing complexity were cautiously introduced into the phone system. In certain backwaters, some of these hybrid systems are still in use. But after 1965, the phone system began to go completely electronic, and this is by far the dominant mode today. Electromechanical systems have "crossbars," and "brushes," and other large moving mechanical parts, which, while faster and cheaper than Leticia, are still slow, and tend to wear out fairly quickly.

But fully electronic systems are inscribed on silicon chips, and are lightning-fast, very cheap, and quite durable. They are much cheaper to maintain than even the best electromechanical systems, and they fit into half the space. And with every year, the silicon chip grows smaller, faster, and cheaper yet. Best of all, automated electronics work around the clock and don't have salaries or health insurance.

There are, however, quite serious drawbacks to the use of computer-chips. When they do break down, it is a daunting challenge to figure out what the heck has gone wrong with them. A broken cordboard generally had a problem in it big enough to see. A broken chip has invisible, microscopic faults. And the faults in bad software can be so subtle as to be practically theological.

If you want a mechanical system to do something new, then you must travel to where it is, and pull pieces out of it, and wire in new pieces. This costs money. However, if you want a chip to do something new, all you have to do is change its software, which is easy, fast and dirt-cheap. You don't even have to see the chip to change its program. Even if you did see the chip, it wouldn't look like much. A chip with program X doesn't look one whit different from a chip with program Y.

With the proper codes and sequences, and access to specialized phone-lines, you can change electronic switching systems all over America from anywhere you please.

And so can other people. If they know how, and if they want to, they can sneak into a microchip via the special phonelines and diddle with it, leaving no physical trace at all. If they broke into the operator's station and held Leticia at gunpoint, that would be very obvious. If they broke into a telco building and went after an electromechanical switch with a toolbelt, that would at least leave many traces. But people can do all manner of amazing things to computer switches just by typing on a keyboard, and keyboards are everywhere today. The extent of this vulnerability is deep, dark, broad, almost mind-boggling, and yet this is a basic, primal fact of life about any computer on a network. Security experts over the past twenty years have insisted, with growing urgency, that this basic vulnerability of computers represents an entirely new level of risk, of unknown but obviously dire potential to society. And they are right. An electronic switching station does pretty much everything Letitia did, except in nanoseconds and on a much larger scale. Compared to Miss Luthor's ten thousand jacks, even a primitive 1ESS switching computer, 60s vintage, has a 128,000 lines. And the current AT&T system of choice is the monstrous fifth-generation 5ESS.

An Electronic Switching Station can scan every line on its "board" in a tenth of a second, and it does this over and over, tirelessly, around the clock. Instead of eyes, it uses "ferrod scanners" to check the condition of local lines and trunks. Instead of hands, it has "signal distributors," "central pulse distributors," "magnetic latching relays," and "reed switches," which complete and break the calls. Instead of a brain, it has a "central processor." Instead of an instruction manual, it has a program. Instead of a handwritten logbook for recording and billing calls, it has magnetic tapes. And it never has to talk to anybody. Everything a customer might say to it is done by punching the direct-dial tone buttons on your subset.

Although an Electronic Switching Station can't talk, it does need an interface, some way to relate to its, er, employers. This interface is known as the "master control center." (This interface might be better known simply as "the interface," since it doesn't actually "control" phone calls directly. However, a term like "Master Control Center" is just the kind of rhetoric that telco maintenance engineers -- and hackers -- find particularly satisfying.)