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Chapter 13. Telecommunications

Until the invention of the telegraph, no reliable communications traveled long distance faster than via a human letter carrier. That didn't stop people from trying, so in the pre-telegraph days a lot of exciting technologies promised to revolutionize communications—smoke signals, semaphore flags, and carrier pigeons were all attempts to break the bond between messenger and message.

The telegraph was able to let the messenger rest his feet and put pigeons back where they belong, atop the heads of dignitaries' statues in the park. With the advent of the telegraph, messages finally were able to travel at the ultimate speed limit of the universe—the speed of light.

Well, not quite. The telegraph only changed the speed of the messenger. It let the pony express rider exchange his steed for Pegasus, but the content of those messages never reached the speed of light. They were also slowed by the interface technology—the telegraph key in the hands of a human being. With fast fingers and a good ear, a 19th-Century telegrapher might squeeze ten words a minute down the wire, equivalent to a bit rate of less than ten per second. At that rate, sending a snapshot home from summer camp might take a month.

Since the advent of the telegraph, technology has concentrated on this other side of the speed issue, making the message move through the data channel faster. Using essentially the same wires as Samuel Morse, you can move data roughly 100,000 times faster through the telephone system and ten million times faster through your home network.

Getting there isn't always easy. The analog nature of your telephone line challenges data signals and imposes strict limits on how fast information can move through the system. The telephone line is an arcane world of strange technologies, all meant to get more speed from the simple telephone wire. It has been a long, hard battle, but one that has paid off. Today's modems now race ahead of the theoretical speed of which information can move through a telephone line. (They can do that because they're no longer really modems, but we're getting ahead of ourselves.)

You can do better. Digital services promise to deliver data 20 times faster than the best modem. Although people aren't switching over to the new, high-speed connections anywhere near as fast as once predicted (that's one of the big reasons the telecommunications industry crashed in 2002), you can be sure someday you will have an all-digital connection.

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