Editing Wireless network (section)

== Wireless links ==
[[File:Wireless network.jpg|thumb|Computers are very often connected to networks using wireless links, e.g. WLANs]]

* ''Terrestrial microwave'' – Terrestrial microwave communication uses Earth-based transmitters and receivers resembling satellite dishes. Terrestrial microwaves are in the low gigahertz range, which limits all communications to line-of-sight. Relay stations are spaced approximately {{convert|48|km|mi|abbr=on}} apart.
* ''[[Communications satellites]]'' – Satellites communicate via microwave radio waves, which are not deflected by the Earth's [[atmosphere]]. The satellites are stationed in space, typically in [[geosynchronous orbit]] {{convert|35400|km|mi|abbr=on}} above the equator. These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals.
* ''Cellular and PCS systems'' use several radio communications technologies. The systems divide the region covered into multiple geographic areas. Each area has a low-power transmitter or radio relay antenna device to relay calls from one area to the next area.
* ''Radio and [[spread spectrum]] technologies'' – Wireless local area networks use a high-frequency radio technology similar to digital cellular and a low-frequency radio technology. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited area. [[IEEE 802.11]] defines a common flavor of open-standards wireless radio-wave technology known as [[Wi-Fi]].
* ''[[Free-space optical communication]]'' uses visible or invisible light for communications. In most cases, [[line-of-sight propagation]] is used, which limits the physical positioning of communicating devices.