megabyte/sec = MBps; megabit/sec = Mbps.
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Bluetooth® is the name of a wireless technology standard for connecting devices that is set to replace cables. It uses radio frequencies in the 2.45 GHz range to transmit information over short distances of generally 33 feet (10 meters) or less. By embedding a Bluetooth® chip and receiver into products, cables that would normally carry the signal can be eliminated.
While entertainment centers, computer systems, handheld PDAs, digital cameras and MP3 players, continue to flourish, manufacturers and end-users alike are plagued by the growing complexity of connecting devices. Proprietary cables, protocols and cradles simply complicate things as companies seek a larger market share while buyers seek user-friendly gadgets that are compatible with other products.
Enter the Bluetooth® standard. Idealized by a group of electronics manufacturers looking for a streamlined solution to a growing problem, it promises to uncomplicate the interconnectivity of devices, easing manufacturing woes and end-user hassles. With embedded Bluetooth® technology, all sorts of devices including cell phones, headsets and earpieces, digital cameras and computers, can easily communicate with each other without cables or setup.
One wireless standard that is already familiar to many is IrDA or infrared. Infrared uses pulses of non-visible light to communicate between two devices, such as a remote control to a television or DVD player. One drawback of IrDA is that there must be a clear line of sight between the two devices, and the other disadvantage is that IrDA normally only operates between two devices at a time. An infrared remote control unit cannot communicate with the DVD player while it is signaling the TV. Bluetooth® overcomes these limitations by using radio waves to send information in packet bursts. The bursts can be sent to any device within 'earshot' allowing communication with several devices at once.
With the popularity of PDA-type products many have come to dread the bane of synchronizing with their computer systems. Cradles, cables, and sometimes luck is needed to ensure a success. Bluetooth® technology eliminates this hassle, as the enabled devices easily recognize each other and communicate spontaneously.
Bluetooth® devices in the house are always communicating with one another as long as they are powered on. Each device sends out a signal, received by the other devices that are sending out their own signals. The devices scan all signals to see if any are addressing it. In this way, Bluetooth® creates a personal-area network (PAN) in the home and the user is not required to do anything special to get the devices to speak to one another. They operate in a perpetual interactive mode by default.
For example, let's assume you are using your cell phone and headset while you copy a DVD from your entertainment center to your desktop -- meanwhile your digital camera is offloading its contents to your laptop. The Bluetooth® devices that have business with one another will initiate their own separate PAN (also called a piconet) and synchronize a random hopping scheme to create interference-free communications. Known as spread-spectrum frequency hopping, the devices will jump among 79 random frequencies within a specified range, changing about 1,600 times per second in perfect unison. The likelihood that a device in another PAN will be using the same frequency at the same time is minute. Hence several individual PANs or piconets can operate in the house without interfering with one another. Each piconet can have 1 master and up to 7 slave devices. Future versions may allow linked piconets called scatternets.
Though other gadgets in the home might utilize the 2.45 GHz range, Bluetooth® separates itself from these by using a very weak signal that "flies under the radar." Conversely these other products rarely cause interference with Bluetooth® because frequency hopping keeps potential interference brief.
The maximum bandwidth for any single channel or frequency is 1 megabyte per second (1Mbps), while individual packets range up to 2,745 bits. There are currently three flavors or classifications of Bluetooth® devices, relative to transmitting range. As the range is increased the signal used in the respective classification is also stronger. Note that Class 3 devices are comparatively rare.
|Class 1||1 milliwatt||Up to 33 feet (10 meters)|
|Class 2||10 milliwatts||Up to 33 feet (10 meters)|
|Class 3||100 milliwatts||Up to 328 feet (100 meters)|
There are also three levels of security available, and if operating in a secure mode, three different security protocols to choose from. However, criticisms have been leveled at these standards, claiming they are too weak for a truly secure network. Due to its limited operating range and purpose, security has not been the main issue in its design. As Class 3 standards, and perhaps future flavors come to light, security will almost certainly improve. Version numbers will also change as the technology improves. Versions 1.1, 1.2 and 2.0 are each slightly different, as will be future editions.
Bluetooth® is not meant to replace wireless LAN technology, mostly because of its range limits. At this point in its newly burgeoning evolution, its main purpose is to simplify the process of connecting products within the home.
Sony Ericsson pioneered this technology before being joined by IBM, Intel, Nokia, and Toshiba in May 1999. Today over 1,000 international electronics manufacturers belong to the Bluetooth® Special Interest Group or SIG. Bluetooth® is named after King Harald Bluetooth of Denmark, who in the 930s consolidated warring factions of Denmark, Norway and Sweden. This ability to establish peaceful communication between differing peoples is a metaphor for the ability to connect devices from differing technologies.
megabyte/sec = MBps; megabit/sec = Mbps.
if you want to download some of your pictures or other files onto your computer using bluetooth, and your mobile phone has bluetooth, how should you do it?
fyi, some bluetooth headsets can be paired to two different devices, and this can be very convenient. i have a headset that i pair to my cellphone and to my computer (for making voip calls). its a piece of cake once you have completed the pairing process.
keep in mind that not all bluetooth headsets are capable of doing this - some older ones can only be paired to one particular device at a time.
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