Latest Mobile Wallpapers Biography
(Source google.com)
Today's communications industry would not be what it is without the contributions made by Richard H. Frenkiel and Joel S. Engel. The big breakthrough came when AT&T Labs researchers Frenkiel and Engel divided wireless communications into a series of cells, then automatically switched callers as they moved so that each cell could be reused. This led to the development of cellular phones and made today’s mobile communications possible. On June 17, 1946 a driver in St. Louis, Missouri., pulled out a handset from under his car's dashboard, placed a phone call and made history. It was the first mobile telephone call. A team including Alton Dickieson, H.I. Romnesand D. Mitchell from Bell Labs, worked more than a decade to achieve this feat. By 1948, wireless telephone service was available in almost 100 cities and highway corridors. Customers included utilities, truck fleet operators and reporters. However, with only 5,000 customers making 30,000 weekly calls, the service was far from commonplace.
That "primitive" wireless network could not handle large call volumes. A single transmitter on a central tower provided a handful of channels for an entire metropolitan area. Between one and eight receiver towers handled the call return signals. At most, three subscribers could make calls at one time in any city. It was, in effect, a massive party line, where subscribers would have to listen first for someone else on the line before making a call. Expensive and far from "mobile", the service cost $15 per month, plus 30 to 40 cents per local call, and the equipment weighed 80 pounds. Just as they would use a CB microphone, users depressed a button on the handset to talk and released it to listen.Improved technology after 1965 brought a few more channels, customer dialing and eliminated the cumbersome handset. But capacity remained so limited that Bell System officials rationed the service to 40,000 subscribers guided by agreements with state regulatory agencies. For example, 2,000 subscribers in New York City shared just 12 channels, and typically waited 30 minutes to place a call. It was wireless, but with "strings" attached.
Something better — cellular telephone service — had been conceived in 1947 by D.H. Ring at Bell Labs, but the idea was not ready for prime time. The system comprised multiple low-power transmitters spread throughout a city in a hexagonal grid, with automatic call handoff from one hexagon to another and reuse of frequencies within a city. The technology to implement it didn't exist, and the frequencies needed were not available. The cellular concept lay barron until the 1960s, when Richard Frenkiel and Joel Engel of Bell Labs applied computers and electronics to make it work.
AT&T turned their work into a proposal to the Federal Communications Commission (FCC) in December 1971. After years of hearings, the FCC approved the overall concept, but licensed two competing systems in each city.
Modern mobile telephony took a giant leap forward on April 3, 1973, when Motorola employee Martin Cooper placed a call to rival AT&T's Bell Labs while walking the streets of New York City talking on the first mobile telephone, a Motorola DynaTAC. In 1978, AT&T conducted FCC-authorized field trials in Chicago and Newark, N.J. Four years later, the FCC granted commercial licenses to an AT&T subsidiary, Advanced Mobile Phone Service Inc. (AMPS). Something better — cellular telephone service — had been conceived in 1947 by D.H. Ring at Bell Labs, but the idea was not ready for prime time. The system comprised multiple low-power transmitters spread throughout a city in a hexagonal grid, with automatic call handoff from one hexagon to another and reuse of frequencies within a city. The technology to implement it didn't exist, and the frequencies needed were not available. The cellular concept lay barron until the 1960s, when Richard Frenkiel and Joel Engel of Bell Labs applied computers and electronics to make it work.
AT&T turned their work into a proposal to the Federal Communications Commission (FCC) in December 1971. After years of hearings, the FCC approved the overall concept, but licensed two competing systems in each city.
Modern mobile telephony took a giant leap forward on April 3, 1973, when Motorola employee Martin Cooper placed a call to rival AT&T's Bell Labs while walking the streets of New York City talking on the first mobile telephone, a Motorola DynaTAC. In 1978, AT&T conducted FCC-authorized field trials in Chicago and Newark, N.J. Four years later, the FCC granted commercial licenses to an AT&T subsidiary, Advanced Mobile Phone Service Inc. (AMPS). AMPS was then divided among the local companies as part of the planning for divestiture. Illinois Bell opened the first commercial cellular system in October 1983. For their pioneering work in cellular telephony, AT&T Labs researchers Richard Frenkiel and Joel Engel earned the National Medal of Technology.Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
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Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
Latest Mobile Wallpapers Mobile Wallpapers Hd 240x320 Love Free Download Animated Hd For Samsung Quotes Friendship Quotess Flowers
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