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8 Guys, 6 Weeks: How the Cell Phone Was (Finally) Invented

Megan Garber
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The first call conducted on a cellular telephone was made for two reasons: show, and spite. Dr. Martin Cooper and a design team at Motorola had just developed a prototype for the device that would go on to change the way humans communicate. So Cooper, appropriately, took to the streets to partake in a tradition that was very, very human: gloating.  

The 'Dazzling' Demo

On April 3, 1973 -- 40 years ago today -- Cooper took an early model of Motorola's DynaTAC phone (a brick phone weighing 2.5 pounds, 9 inches long and 5 inches deep, with about 20 minutes of battery life) to the streets of New York City. He pressed the phone's "off hook" button. And he made a call to the land line of Bell Labs, where he was connected to his counterpart, and chief rival, Joel Engel. Cooper, the legend goes, proceeded to inform Engel that Motorola had beaten Bell to the technology that would be the next pivotal step in telephony. "Joel, this is Marty," Cooper said. "I'm calling you from a cell phone, a real handheld portable cell phone."

Cooper, in doing all this, made quite a scene. Telephones, at the point, were not things you could just carry around with you as you walked. (Cooper liked to joke that the DynaTAC's limited talk time wasn't technically a problem -- since "you couldn't hold that phone up for that long.") So the vision of a guy walking around near Radio City Music Hall, talking animatedly into a large hunk of plastic, was a spectacle. Even for a city that was used to spectacles. "As I walked down the street while talking on the phone," Cooper would later recall, "sophisticated New Yorkers gaped at the sight of someone actually moving around while making a phone call." 

And that, of course, was the point. "We wanted to do a dazzling demonstration," Cooper said. The team's goal wasn't just to invent something; it was to let the world know, in as striking a way as possible, that the something had been invented. So Cooper enjoyed -- and exploited -- the moment. "I made numerous calls," he remembered, "including one where I crossed the street while talking to a New York radio reporter -- probably one of the more dangerous things I have ever done in my life."

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Martin Cooper, holding a model of the DynaTAC, accepts a special achievement award during the 15th annual Webby Awards in June 2011. (Reuters)

'What the Hell's a Portable Cell Phone?'

The technology that fueled Cooper's demo -- which ended with the technologist triumphantly modeling his phone to a gaggle of reporters assembled for the occasion at the Midtown Hilton -- had been in the works, of course, long before Cooper strode out onto 6th Avenue. (Cooper knew it would work because he had previously demonstrated the phone for the group that was arguably his most important audience: the FCC.) The cell phone was the culmination of a good, old-fashioned race to invention, much like the one that led to the telephone itself. And it was spurred along not only by competition among R&D departments at rival corporations, but also by technological progress -- progress that would be inevitable if only consumer hardware could catch up to it. As early as 1947, engineers at Bell Labs had imagined the standard cellular network. By the 1970s, car phones -- the original mobile phones -- were in regular, if not widespread, use. Human-centered mobile phones were the next obvious step in telephony's evolution. 

The government was spurring things along, too. The Federal Communications Commission, at the time, was deliberating whether to allow AT&T to set up a network that would provide wireless phone service in local markets, ostensibly for use with car phones. Not only would this proposal give AT&T an effective monopoly in those markets; it would also mean that car phones, rather than person-based mobile phones, would likely become the dominant technology as mobile phones prolfierated. Cooper and his colleagues saw where things were heading -- and they wanted to change the direction, and then lead the way there.

Rudy Krolopp, lead designer of the device that would become the Motorola DynaTAC 8000X, recalled the frantic weeks that led, finally, to the cell phone. "Marty called me to his office one day in December 1972 and said, 'We've got to build a portable cell phone,'" Krolopp says. "And I said, 'What the hell's a portable cell phone?'"

They would answer the question by inventing it. Krolopp and his team were given six weeks -- yep, a month and a half -- to get the job done. After his meeting with Cooper, Krolopp quickly assembled his staff. "We sprung it on the engineers one day," he said. "There were only eight guys in the room." Cooper laid out the problem -- and the goal -- to the tiny team. And then he said, "Anybody who doesn't believe this can be done, leave the room."

Nobody left.

A Portable Duplex Radio Telephone System

Instead, the team designed, and designed some more, until they came up with the solution: the clunky-yet-sleek device that Cooper demo'ed on the streets of New York in early April 1973, effectively "claiming" the portable phone's invention. The team owed much of its success to Motorola's existing expertise with semiconductors, which allowed it to develop the core electrical infrastructure of the device that would become the DynaTAC. Then came the question of the body. Krolopp and his team offered up five potential shells for the phone, from the flat to the curved to the folding. Cooper ended up choosing the prototype that was the bulkiest, but the most practical: the one that best resembled phones as they existed at the time. The team affectionately dubbed it "the shoe."

In October 1973, the whole team filed a patent -- not just for the phone itself, but for "a radio telephone system." They imagined that system like so:


And they described their invention like this:

A portable duplex radio telephone system includes at least one base station transmitter having a predetermined base transmission range, and a plurality of portable or mobile units each having a portable maximum transmission range pre-determinately shorter than the base transmission range. Satellite receivers are deployed about the base within the base station transmission range for receiving transmissions from the portable units. The station transmitter transmits signals on a channel and on at least one communications channel. Each transmitter signalling and communications channel has a frequency that is paired or associated with receiving frequency of the satellite receivers. In a multiple base station system the portable receiver means for scanning the base station transmitter signalling frequencies and for tuning the portable transmitter to the signalling frequency associated with the frequency of the strongest signalling signal received from the base transmitter. When communication is initiated the portable transmitter and receiver are automatically retuned to one of the communications channels as determined by the strongest signalling frequency received by the portable receiver and by channel availability.

'Naturally, Fundamentally, and Inherently Mobile'

That was, however, just the technical explanation for what they had done. In person, the inventors were much more philosophical about the device they had just unleashed -- in a prototype form, at least -- unto the world. They knew what they had on (and in) their hands, appreciating from the start the extent to which mobile phones would change the way we relate to each other. So many of the innovations that would come later -- the GPS devices and the smartphones and the tablet computers -- would radiate from Cooper's conviction that humans, rather than machines, should act as nodes of communication. (Cooper imagined a time, in fact, when phones would be "embedded under your skin.") Much of the point of the whole race to the cellular had been to ensure that human-based mobile phones, rather than car-based, would win the day. 

They did. And Cooper saw that as as natural, if not fully inevitable: a return to humans' natural inclination to be unencumbered from the tyranny of adjacency. "I have a mantra that people are naturally, fundamentally, and inherently mobile," Cooper explains. And after cell phones, no longer would physical location in a certain place -- at home, at work, near a thing connected to another thing -- be a precondition for communication. Motorola's invention would, eventually, change the definition of "connection" in the first place. 

"The father of the cellular phone" actually preferred to call his creation the "personal telephone," and he regarded the device as "something that would represent an individual, so you could assign a number not to a place, not to a desk, not to a home, but to a person." Forty years ago, telephony got its first taste of that personification. The cell phone connected us on a network. But its point was to free us of that network.

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