Wireless

Wireless

Wireless is a term used to describe telecommunications in which electromagnetic waves (rather than some form of wire) carrythe signal over part or all of the communication path. Some monitoring devices, such as intrusionalarms, employ acoustic waves at frequencies above the range of human hearing; these are also sometimes classified as wireless.

Common examples of wireless equipment in use today include:
1. celluler phones and pagers -- provide connectivity for portable and mobile applications, both personal and business
2. Global Positioning System (GPS) -- allows drivers of cars and trucks, captains of boats and ships, and pilots of aircraft to ascertain their location anywhere on earth
3. Cordless computer peripherals -- the cordless mouse is a common example; keyboards and printers can also be linked to a computer via wireless
4. Cordless telephone sets -- these are limited-range devices, not to be confused with cell phones
5. Home-entertainment-system control boxes -- the VCR control and the TV channel control are the most common examples; some hi-fi sound systems and FM broadcast receivers also use this technology
6. Remote garage-door openers -- one of the oldest wireless devices in common use by consumers; usually operates at radio frequencies
7. Two-way radios -- this includes Amateur and Citizens Radio Service, as well as business, marine, and military communications
8. Baby monitors -- these devices are simplified radio transmitter/receiver units with limited range
9. satellite television -- allows viewers in almost any location to select from hundreds of channels
10. wireless LANs or local area networks -- provide flexibility and reliability for business computer users


wireless LAN
A wireless LAN (or WLAN, for wireless local area network, sometimes referred to as LAWN, for local area wireless network) is one in which a mobile user can connect to a local area network (LAN) through a wireless (radio) connection. The IEEE 802.11 group of standards specify the technologies for wireless LANs. 802.11 standards use the Ethernet protocol and CSMA/CA(carrier sense multiple access with collision avoidance) for path sharing and include an encryption method, the Wired Equivalent Privacy algorithm.


Wireless can be divided into:

1. fixed wireless-- the operation of wireless devices or systems in homes and offices, and in particular, equipment connected to the Internet via specialized modems
2. Mobile wireless -- the use of wireless devices or systems aboard motorized, moving vehicles; examples include the automotive cell phone and PCS (personal communications services)
3. Portable wireless -- the operation of autonomous, battery-powered wireless devices or systems outside the office, home, or vehicle; examples include handheld cell phones and PCS units
4. IR wireless -- the use of devices that convey data via IR (infrared) radiation; employed in certain limited-range communications and control systems