The telephone is a truly ubiquitous item in the American, and global, environment. Telephones are in nearly every American home and office, and in many automobiles. The telephone has changed the way Americans communicate, bringing instant communication into situations where letters or telegrams would have once been the only way to communicate (such as long distance communications. In recent years, the telecommunications revolution has resulted in much more than just voice being transmitted over phone wires: data, in the form of modems and faxes, is now commonly sent over the wire network once designed for voice transfer. However, the wired telephone has received increased competition from an invention which happened on the scene at approximately the same time: radio. The great difference between these two technologies is that radio communication does not require dedicated wires, which is how phones (actually radios) can now be installed in automobiles. This research examines the proliferation of so-called wireless communication and considers the future of this technology.
The telephone transmits and receives sound by means of wires in electric circuits. Modern telephone transmitters are basically carbon microphones which contain loosely packed carbon grains. When someone speaks into the microphone, a diaphragm vibrates, causing the carbon grains to be compressed and released, causing the current flow in the associated electric circuit to vary. The current, when transmitted to a distant identical instrument, causes the diaphragm in it to vibrate in response to the fluctuations induced by the nearby magnetic field. Telephone lines can use open-wire lines; lead-sheathed cables consisting of many lines; coaxial cables; and, most recently, glass fibers. Coaxial cables and fiber-optic lines are placed underground, but other cables may be either overhead or underground.
Long-distance transmission of telephone messages is of...