Wireless
From Wikipedia, the free encyclopedia
- This article is about wireless technology in general. For the article on wireless communication see Wireless communication.
- For the article on wireless networking see Wireless networking.
The term wireless is normally used to refer to any type of electrical or electronic operation which is accomplished without the use of a "hard wired" connection. Some of these operations may also be accomplished with the use of wires if desired, while others, such as long range communications, are impossible or impractical to implement with the use of wires. The term is commonly used in the telecommunications industry to refer to telecommunications systems (e.g., radio transmitters and receivers, remote controls, computer networks, network terminals, etc.) which use some form of energy (e.g.,radio frequency (RF), infrared light, laser light, visible light, acoustic energy, etc.) to transfer information without the use of wires.[1] Information is transferred in this manner over both short and long distances.
The term "wireless" should not be confused with the term "cordless", which is generally used to refer to powered electrical or electronic devices that are able to operate from a portable power source (e.g., a battery pack) without any cable or cord to limit the mobility of the cordless device through a connection to the mains power supply. It is interesting to note that some cordless devices, such as cordless telephones, are also wireless in the sense that information is transferred from the cordless telephone to the telephone's base unit via some type of wireless communications link. This has caused some disparity in the usage of the term "cordless", for example in Digital Enhanced Cordless Telecommunications.
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[edit] Examples of wireless technology at work
[edit] Security systems
- One common example of an operation or operations where the implementation of wireless technology may supplement or replace hard wired implementations is in security systems for homes or office buildings. The operations that are required (e.g., detecting whether a door or window is open or closed) may be implemented with the use of hard wired sensors or they may be implemented with the use of wireless sensors which are also equipped with some type of wireless transmitter (e.g., infrared, radio frequency, etc.) to transmit the information concerning the current state of the door or window.
[edit] Television remote control
- Another example would be the use of a wireless remote control unit to replace the old hard wired remote control units that were sometimes used in the television industry. Some televisions were previously manufactured with hard wired remote controls which plugged in to a receptacle or jack in the television whereas more modern televisions use wireless (generally infrared) remote control units.
[edit] Cellular telephones
- Perhaps one of the most well known examples of wireless technology in action is the cellular telephone. These instruments use radio waves to enable the operator to make phone calls from many locations world-wide. They can be used anywhere that there is a cellular telephone site to house the equipment that is required to transmit and receive the signal that is used to transfer both voice and data to and from these instruments. (For more information see the article on mobile phones).
[edit] History
The term "wireless" came into public use to refer to a radio receiver or transceiver (a dual purpose receiver and transmitter device), establishing its usage in the field of wireless telegraphy early on; now the term is used to describe modern wireless connections such as in cellular networks and wireless broadband Internet. It is also used in a general sense to refer to any type of operation that is implemented without the use of wires, such as "wireless remote control", "wireless energy transfer", etc. regardless of the specific technology (e.g., radio, infrared, ultrasonic, etc.) that is used to accomplish the operation.
[edit] Heinrich Rudolf Hertz
Possibly the most important discovery in the history of wireless technology was the demonstration by Heinrich Rudolf Hertz in 1888 that electromagnetic waves exist[2][3] as predicted by James Clerk Maxwell and Michael Faraday. He also proved that these waves could be transmitted and caused to travel through space and that they were able to be received by an experimental apparatus.[2][3] The experiments of Hertz proved to be very important to the fields of wireless communication and remote control, though practical applications of the technology would be implemented by others.
[edit] Nikola Tesla
Some principles and inventions of wireless technology can be found in the lectures, patent record, and other accounts of the electrical engineer Nikola Tesla (such as his 1916 deposition on the history of wireless and radio technology: 'Nikola Tesla On His Work With Alternating Currents And Their Application to Wireless Telegraphy, Telephony, and Transmission of Energy, Anderson, Leland, ed., Published 1992).
[edit] See also
[edit] References
- ^ ATIS Committee T1A1 Performance and Signal Processing. ANS T1.523-2001, Telecom Glossary 2000 http://www.atis.org/tg2k/
- ^ a b Story, Alfred Thomas (1904). A story of wireless telegraphy. New York, D. Appleton and Co..
- ^ a b Eugenii Katz, "Heinrich Rudolf Hertz ".
[edit] External links
[edit] Patents
- U.S. Patent 1642420 , S. Loewe, "Wireless Receiving Apparatus"
- U.S. Patent 1754875 , E. E. Clement, "Radiophone desk set"
