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Infrared signals can be either directed (as with a tv remote) or diffused (like normal sunlight).
Direct Infrared Technology
Direct infrared light needs a clear line of sight to make a connection. The most familiar direct infrared communication device is the TV remote control. A connection is made by transmitting data using two different intensities of infrared light to represent the 1s and 0s. The infrared light is transmitted in a 30-degree cone giving some flexibility in orientation of the equipment, but not much. Some disadvantages exist with direct connections, one of which is range, usually restricted to less then 3 feet. Also, because it needs a clear line of sight, the equipment must be pointing towards the general area of the receiver or the connection is lost.
In order to promote the use of direct infrared systems an organization called the Infrared Data Association (IrDA) has been established. IrDA is an association of over 130 companies, including IBM, Intel and Motorola, formed to create interoperable, low cost infrared data interconnection standards. The first of these standards (IrDA 1.0) supported data rates of 115.2Kbits/s. The newer standard (IrDA 1.1) now supports higher data rates of 1.15 & 4Mbps. Today most new laptop computers come with IrDA ports as standard as well as printers and a whole range of network and access products designed to take advantage of the new technology.
What would appear to be a restrictive wireless technology is actually quite well suited to wireless LANs. The technology is ideal for creating a peer to peer network. As most laptops already have IrDA ports, users in a meeting would simply be able to point their laptops towards each other and the network would be formed. As far as infrastructure networks go, access points do exist which allow IrDA equipped laptop computers to connect directly to the network, although restrictions in range and true mobility a little difficult. For example, an office that has the access points always spread around on desks and benches would allow mobile users to sit down and connect without the inconvenience of having to plug in to the network.
In order to be useful as a replacement to traditional methods of connecting to the network, the infrared link would have to perform at 4Mb/s the IrDA1.1 standard. However, there are many different types to infrared technology invented from different companies, which makes the infrared technology a bit difficult to implement into our life. Microsoft is currently developing its IrDA LAN driver V3.0 that will transmit at 115Kb/s, 1Mb/s and 4Mb/s. Hopefully that would be the standard for the infrared technology. Therefore, so far most laptop manufacturers have chosen to wait for version 3.So far the infrared industry still considers the direct infrared technology to be a very useful solution for connecting laptop computers to the network. Although it is not known how soon Microsoft will release version 3.0 of itís IrDA LAN driver, the beta development kit is already available to download from their web site. If one were considering using this technology today it is a simple matter of finding which laptops are compatible with the preferred access point.
Diffuse Infrared Technology
Diffuse infrared technology operates by flooding an area with infrared light, in much the same way as a conventional light bulb illuminates a room. The infrared signal bounces off the walls and ceiling so that a receiver can pick up the signal regardless of orientation. Diffuse infrared technology is a compromise between direct infrared and radio technology. It combines the advantages of high data rates from infrared and the freedom of movement from radio. However, even though its speed is up to 4Mbits/s, but it is shared among all the users, unlike direct infrared. Although people can enjoy its speed and its mobility, but it is restricted within a certain range, such as a room. It doesnít go through a wall.
How does it work?? We just simply connect a hub that made for the infrared with a wired LAN in a room. It will then create infrared signals and flood them in the room.Diffuse infrared technology has begun to establish itself as a real alternative to radio in wireless LAN systems. However, lack of movement towards this technology by the large networking manufacturers (IBM for example recently abandoned it's diffuse infrared product) has meant very few systems are commercially available. Those, which do exist, do not show the refinement of the radio systems produced by the large manufactures. Despite these initial problems, the technology has the potential to provide very high data rates and good coverage for most applications.
For more on diffused method, click HERE