Friday, July 07, 2006

computer

Bluetooth is an industrial specification for wireless personal area networks (PANs), also known as IEEE 802.15.1. Bluetooth provides a way to connect and exchange information between devices like personal digital assistants (PDAs), mobile phones, laptops, PCs, printers and digital cameras via a secure, globally unlicensed short range radio frequency.
The name Bluetooth was born from the 10th century king of Denmark, King Harald Bluetooth (whose surname is sometimes written as Bluetooh), who engaged in diplomacy which led warring parties to negotiate with each other. The inventors of the Bluetooth technology thought this a fitting name for their technology, which allowed different devices to talk to each other.[1]. The name of the king in Danish was Harald Blåtand and the Bluetooth logo is based on the H and B runes.
Bluetooth is in a variety of new products such as phones, printers, modems, and headsets to name a few. Bluetooth is acceptable for situations when two or more devices are in close proximity with each other and don’t require high bandwidth. Bluetooth is most commonly used with cell phones, either using a Bluetooth headset or transferring files from phones to computers. Because Bluetooth uses short range radio frequencies it is not as effective for setting up networks that can be accessed from remote locations. Wi-Fi technology is better suited for this purpose.
Wi-Fi
Wi-Fi uses the same radio frequencies as Bluetooth, but with higher power consumption resulting in a stronger connection. As mentioned earlier, Wi-Fi is sometimes called a wireless Ethernet. Although this is not entirely true it provides us with an idea of what Wi-Fi is capable of. Wi-Fi is better suited for setting up networks since it is a faster connection and has increased security over Bluetooth. Wi-Fi is popular among the computing world, virtually all new laptop computers come with Wi-Fi built in, and all desktop computers are able to be adapted to have a Wi-FI connection. However cell phones do not have this ability.
A way to get Internet access, the term Wi Fi is a play upon the decades-old term HiFi that describes the type of output generated by quality musical hardware, Wi Fi stands for Wireless Fidelity and is used to define any of the wireless technology in the IEEE 802.11 specification - including (but not necessarily limited to) the wireless protocols 802.11a, 802.11b, and 802.11g. The Wi-Fi Alliance is the body responsible for promoting the term and its association with various wireless technology standards.

BROADBAND refers to telecommunication in which a wide band of frequencies is available to transmit information. Because a wide band of frequencies is available, information can be multiplexed and sent on many different frequencies or channels within the band concurrently, allowing more information to be transmitted in a given amount of time (much as more lanes on a highway allow more cars to travel on it at the same time). Related terms are wideband (a synonym), baseband (a one-channel band), and narrowband (sometimes meaning just wide enough to carry voice, or simply "not broadband," and sometimes meaning specifically between 50 cps and 64 Kpbs).

Bandwidth
A range within a band of frequencies or wavelengths.
(2) The amount of data that can be transmitted in a fixed amount of time. For digital devices, the bandwidth is usually expressed in bits per second(bps) or bytes per second. For analog devices, the bandwidth is expressed in cycles per second, or Hertz (Hz).
The bandwidth is particularly important for I/O devices. For example, a fast disk drive can be hampered by a bus with a low bandwidth. This is the main reason that new buses, such as AGP, have been developed for the PC.


MMS
Short for Multimedia Message Service, a store-and-forward method of transmitting graphics, video clips, sound files and short text messages over wireless networks using the WAP protocol. Carriers deploy special servers, dubbed MMS Centers (MMSCs) to implement the offerings on their systems. MMS also supports e-mail addressing, so the device can send e-mails directly to an e-mail address. The most common use of MMS is for communication between mobile phones.
MMS, however, is not the same as e-mail. MMS is based on the concept of multimedia messaging. The presentation of the message is coded into the presentation file so that the images, sounds and text are displayed in a predetermined order as one singular message. MMS does not support attachments as e-mail does.
To the end user, MMS is similar to SMS.
SMS (Short Message Service) is a service for sending messages of up to 160 characters to mobile phones that use Global System for Mobile (GSM) communication. GSM and SMS
3G (or 3-G) is short for third-generation technology. It is usually used in the context of cell phones. The services associated with 3G provide the ability to transfer both voice data (a telephone call) and non-voice data (such as downloading information, exchanging email, and instant messaging).
WAP

Short for the Wireless Application Protocol, a secure specification that allows users to access information instantly via handheld wireless devices such as mobile phones, pagers, two-way radios, smartphones and communicators.
WAP supports most wireless networks. These include CDPD, CDMA, GSM, PDC, PHS, TDMA, FLEX, ReFLEX, iDEN, TETRA, DECT, DataTAC, and Mobitex.
WAP is supported by all operating systems. Ones specifically engineered for handheld devices include PalmOS, EPOC, Windows CE, FLEXOS, OS/9, and JavaOS.
WAPs that use displays and access the Internet run what are called microbrowsers--browsers with small file sizes that can accommodate the low memory constraints of handheld devices and the low-bandwidth constraints of a wireless-handheld network.
IrDA


Short for Infrared Data Association, a group of device manufacturers that developed a standard for transmitting data via infrared light waves. Increasingly, computers and other devices (such as printers) come with IrDA ports. This enables you to transfer data from one device to another without any cables. For example, if both your laptop computer and printer have IrDA ports, you can simply put your computer in front of the printer and output a document, without needing to connect the two with a cable.
IrDA ports support roughly the same transmission rates as traditional parallel ports. The only restrictions on their use is that the two devices must be within a few feet of each other and there must be a clear line of sight between them

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