At the outset, people weren't quite sure how to use this newfangled device, but they knew they wanted one—or more accurately, two, because telephones were initially sold in pairs. (The first customer, a Boston banker, leased a pair for his office and home, plus a private line to join them.) Telephony quickly found a more flexible form, however. The year 1878 saw the creation of the first commercial exchange, a manual switching device that could form pathways between any of 21 subscribers. Soon that exchange was handling 50 subscribers, and bigger exchanges, with operators handling a maze of plugs and cords to open and close circuits, quickly began popping up in communities all across America. Although the Bell system would stick with operators and plugboards for a while, an automated switchboard became available in the 1890s, invented by an Indiana undertaker named Almon Strowger, who suspected that local telephone operators were favoring his competitors. His apparatus made a connection when a caller pressed two buttons on a telephone a certain number of times to specify the other party. Soon, a 10-digit dialing wheel replaced the buttons, and it would hold sway until Touch-Tone dialing—a faster method that expressed numbers as combinations of two single—frequency tones-arrived on the scene in the 1960s.
At the start of the 20th century, many basic features of telephone technology were in place. By then, the human voice was captured by a method that would remain standard for many decades: In the microphone, sound waves pressed carbon granules together, changing their electrical resistance and imposing an analogous pattern of variations on a current passing through them. The signal was carried by a pair of copper wires rather than the single iron or steel wire of the dawn years. Copper's electrical resistance was only a tenth as much, and random noise was dramatically reduced by using two wires instead of completing the circuit through the ground, as telegraphy did. In cities, unsightly webs of wires were minimized by gathering lines in lead pipes about 2 inches in diameter. The early cables, as such bundles were called, held a few dozen pairs; by 1940 about 2,000 could be packed into the pipe. At the start of the 20th century, many basic features of telephone technology were in place. By then, the human voice was captured by a method that would remain standard for many decades: In the microphone, sound waves pressed carbon granules together, changing their electrical resistance and imposing an analogous pattern of variations on a current passing through them. The signal was carried by a pair of copper wires rather than the single iron or steel wire of the dawn years. Copper's electrical resistance was only a tenth as much, and random noise was dramatically reduced by using two wires instead of completing the circuit through the ground, as telegraphy did. In cities, unsightly webs of wires were minimized by gathering lines in lead pipes about 2 inches in diameter. The early cables, as such bundles were called, held a few dozen pairs; by 1940 about 2,000 could be packed into the pipe. As other countries caught the telephone contagion, their governments frequently claimed ownership, but the private enterprise model prevailed in the United States, and a multitude of competitors leaped into the business as the original Bell patents expired. At the turn of the 20th century, the Bell system accounted for 856,000 phones, and the so-called independents had 600,000. Corporate warfare raged, with AT&T buying up as many of the upstarts as possible and attempting to derail the rest by refusing to connect their lines to its system. Two decades later AT&T secured its supremacy when the U.S. Senate declared it a "natural monopoly"—one that would have to accept tight governmental regulation. During these years, all the contenders experimented with sales gimmicks such as wake-up calls and telephone-delivered sermons. Price was a major marketing issue, of course, and it dropped steadily. At the beginning of the century, the Bell system charged $99 per thousand calls in New York City; by the early 1920s a flat monthly residential rate of $3 was typical. As the habit of talking at a distance spread, some social commentators worried that community ties and old forms of civility were fraying, but the telephone had unstoppable momentum. By 1920 more than a third of all U.S. households were connected. Most had party lines, which generally put two to four households on the same circuit and signaled them with distinctive rings. Phone company publications urged party line customers to keep calls brief and not to eavesdrop on their neighbors, but such rules were often honored only in the breach.
Extending the range of telephone calls was a key engineering challenge, much tougher than for telegraphy because the higher frequency of voice-based signals caused them to fade faster as they traveled along a wire. Early on, a device called a loading coil offered a partial cure. Independently invented in 1899 by Michael Pupin of Columbia University and George Campbell of AT&T, it basically consisted of a coil of wire that was placed along a line every 6,000 feet or so, greatly diminishing attenuation in the range of frequencies suitable for voice transmission. Two years later commercial service began between Philadelphia and Chicago, and by 1911 a long-distance line stretched all the way from New York to Denver. But transcontinental service remained out of reach until Bell engineers began experimenting with the triode vacuum tube, patented in 1907 by the radio pioneer Lee De Forest as "A Device for Amplifying Feeble Electrical Currents." Extending the range of telephone calls was a key engineering challenge, much tougher than for telegraphy because the higher frequency of voice-based signals caused them to fade faster as they traveled along a wire. Early on, a device called a loading coil offered a partial cure. Independently invented in 1899 by Michael Pupin of Columbia University and George Campbell of AT&T, it basically consisted of a coil of wire that was placed along a line every 6,000 feet or so, greatly diminishing attenuation in the range of frequencies suitable for voice transmission. Two years later commercial service began between Philadelphia and Chicago, and by 1911 a long-distance line stretched all the way from New York to Denver. But transcontinental service remained out of reach until Bell engineers began experimenting with the triode vacuum tube, patented in 1907 by the radio pioneer Lee De Forest as "A Device for Amplifying Feeble Electrical Currents."
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