Wireless Access Point(AP)
Wireless access points connect a group of wireless devices to an adjacent wired LAN. An access point is similar to an Ethernet hub, relaying data between connected wireless devices in addition to a (usually) single connected wired device, most often an Ethernet hub or switch, permitting wireless devices to communicate with other wired devices. An AP can be used ton create a free wifi spot and if it is configured without any security, the network becomes vulnerable to attacks so much that wifi dummies can easily access the internet through it.
Wireless Adapter
Wireless adapters allow computer devices to connect to a wifi (wireless) network. These adapters connect to these devices using various external or internal interconnects such as PCI, miniPCI, USB, ExpressCard, Cardbus and PC card. Most newer laptop computers are equipped with internal adapters. Internal cards are generally more difficult to install.
Wireless routers integrate a WAP, Ethernet switch, and internal Router firmware application that provides IP Routing, NAT, and DNS forwarding through an integrated WAN interface. A wireless router allows wired and wireless ethernet LAN devices to connect to a (usually) single WAN device such as cable modem or DSL modem. A wireless router allows all these devices (mainly the access point and router) to be configured through one central utility. A router can be configured in such a way that it becomes a free wifi broadcasting spot if done without security in mind.
This utility is most usually an integrated web server which serves web pages to wired and wireless LAN clients and often optionally to WAN clients. This utility may also be an application that is run on a desktop computer such as Apple's AirPort.
Wireless Ethernet bridges connect a wired network to a wireless network. This is different from an access point in the sense that an access point connects wireless devices to a wired network at the . Two wireless bridges may be used to connect two wired networks over a wireless link, useful in situations where a wired connection may be unavailable, such as between two separate homes.
Wireless range extenders or wireless repeaters can extend the range of an existing wireless network. Range extenders can be strategically placed to elongate a signal area or allow for the signal area to reach around barriers such as those created in L-shaped corridors. Wireless devices connected through repeaters will suffer from an increased latency for each hop. Additionally, a wireless device connected to any of the repeaters in the chain throughput that is limited by the weakest link between the two nodes in the chain from which the connection originates to where the connection ends.
Most commercial devices (routers, access points, bridges, repeaters) designed for home or business environments use either RP-SMA or RP-TNC antenna connectors. PCI wireless adapters also mainly use RP-SMA connectors. Most PC card and USB wireless only have internal antennas etched on their printed circuit board while some have MMCX connector or MC-Card external connections in addition to an internal antenna. A few USB cards have a RP-SMA connector.
Most Mini PCI wireless cards use Hirose U.FL connectors, but cards found in various wireless appliances contain all of the connectors listed. Many high-gain (and home made antennas) use the Type N connector more commonly used by other radio communications methods.
Non-standard devices
The longest link ever achieved was by the Swedish space agency. They attained 310 km, but used 6 watt amplifiers to reach an overhead stratospheric balloon. The longest link without amplification was 279 km in Venezuela, 2006
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