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Mobile Phones

  • Daniel B. Garrie,
  • Leo M. Gordon,
  • Bradford Newman

摘要

Mobile phones are devices that make and receive communications, most often as telephone calls and text messages, by connecting to a cellular network. Mobile phone services have existed since 1973, allowing people to communicate anywhere without the need for fixed telephone lines. From large, bulky, and expensive equipment carried in briefcases to sleek, pocket-sized devices readily afforded by most people, they have evolved in size, price, and functionality.