CELLULAR RADIO TELEPHONE
INTRODUCTION:
Cellular radio telephone, also called as cellular telephone or cell phone consists of a low-powered, lightweight radio transceiver (combination transmitter receiver), which provides voice telephone service to mobile users. Cellular telephones operate as portable telephones; whereas normal telephones require a cord that connects to a jack in order to access the extensive wire line networks operated by local telephone companies, cellular telephones are not restricted by a cord. Cellular telephones have become very popular with professionals and consumers as a way to communicate while away from their regular phones, while traveling or when in remote locations lacking regular phone service.
HOW DOES IT WORK?????
Cellular telephones work by transmitting radio waves to cellular towers. These towers vary in the area they cover and can receive nearby cellular telephone signals from distances as short as 1.5 to 2.4 km to distances as long as 48 to 56 km. The area a tower can cover is referred to as a cell; the towers within these cells are networked to a central switching station, usually by wire, fiber-optic cable, or microwave. The central switching station handling cellular calls in a given area is directly connected to the rest of the wired telephone system. Cellular calls are picked up by the towers and relayed to the rest of the telephone network. Since the cells overlap, as a mobile caller moves from one cell into another, the towers “hand off” the call so communication is uninterrupted.
HISTORY:
The first commercial cellular telephones were tested in the late 1970s by Illinois Bell in Chicago, and they were a great success. Cellular service carriers began nationwide operations in the mid 1980’s. The radio signals often interfered with those of other commercial radios, and due to the technology of the day the frequencies could not be reused as they can today. Therefore, limited numbers of channels were available for callers, and the service was unreliable and costly. Because of the consumer demand for cellular telecommunications, the Federal Communications Commission (FCC) in the mid-1990s authorized up to six additional mobile telephone service providers in each service area.
INTRODUCTION:
Cellular radio telephone, also called as cellular telephone or cell phone consists of a low-powered, lightweight radio transceiver (combination transmitter receiver), which provides voice telephone service to mobile users. Cellular telephones operate as portable telephones; whereas normal telephones require a cord that connects to a jack in order to access the extensive wire line networks operated by local telephone companies, cellular telephones are not restricted by a cord. Cellular telephones have become very popular with professionals and consumers as a way to communicate while away from their regular phones, while traveling or when in remote locations lacking regular phone service.
HOW DOES IT WORK?????
Cellular telephones work by transmitting radio waves to cellular towers. These towers vary in the area they cover and can receive nearby cellular telephone signals from distances as short as 1.5 to 2.4 km to distances as long as 48 to 56 km. The area a tower can cover is referred to as a cell; the towers within these cells are networked to a central switching station, usually by wire, fiber-optic cable, or microwave. The central switching station handling cellular calls in a given area is directly connected to the rest of the wired telephone system. Cellular calls are picked up by the towers and relayed to the rest of the telephone network. Since the cells overlap, as a mobile caller moves from one cell into another, the towers “hand off” the call so communication is uninterrupted.
HISTORY:
The first commercial cellular telephones were tested in the late 1970s by Illinois Bell in Chicago, and they were a great success. Cellular service carriers began nationwide operations in the mid 1980’s. The radio signals often interfered with those of other commercial radios, and due to the technology of the day the frequencies could not be reused as they can today. Therefore, limited numbers of channels were available for callers, and the service was unreliable and costly. Because of the consumer demand for cellular telecommunications, the Federal Communications Commission (FCC) in the mid-1990s authorized up to six additional mobile telephone service providers in each service area.
1 comment:
thanks bro
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