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Before we get into the particulars, a bit of history is in order, for any discussion focusing on Bluetooth would not be complete without including the origin of this somewhat strange name. In 1994, a group of engineers from Swedish telecommunications manufacturer Ericsson developed the technology to connect mobile phones to their accessories wirelessly. Then, in 1998, the Bluetooth Special Interest Group (SIG) was formed, and it included industry giants such as IBM, Intel, Nokia, and Toshiba, who then went to work with Ericsson on developing an open-standards specification that would work across multiple hardware and software platforms, not just mobile phones. This project, which united a multinational alliance of companies, was code-named Bluetooth after Kink Harald Blatand, who ruled Denmark during the 20th century and who reportedly was responsible for uniting Denmark and Norway as well as bringing Christianity to the Scandinavian territories. Translated, the name Blatand means “Bluetooth.”
The Bluetooth SIG was later joined by 3Com, Lucent, Microsoft and Motorola. As a result, Bluetooth technology is showing up, albeit slowly, in PC’s, handhelds, printers, headphones, DV camcorders and other peripherals, and is poised to become the next standard for exchanging information wirelessly across short distances.
How it works
Unlike infrared (IrDA), which uses a beam of light to transmit data and is found in many PDA devices, remote controls, and wireless keyboards, Bluetooth uses a radio frequency (2.4 GHz) to communicate. The biggest advantage that Bluetooth has over IR is that one device doesn’t need to be in the line of sight of the device that it’s communicating with, so it can work through walls and floors. For example, with IR, if somebody walks between your TV set and remote control, the beam is broken and the transmission is lost until the obstruction is removed. Not so with Bluetooth.
While the 2.4 GHz radio band is used by lots of other devices (including cordless phones, baby monitors and 802.11b wireless networks), interference with these devices is unlikely due to Bluetooth’s spread-spectrum frequency-hopping technology. Basically what this means is that Bluetooth devices randomly change frequencies (between the 2.40 and 4.48 GHz range) over a thousand times per second, using 79 different channels within the spectrum, so even on the chance that two devices hit the same exact frequency, the disruption will be negligible.
Another cool-feature of this technology is that Bluetooth-enabled devices can find each other without the user’s having to do anything. For example, when two Bluetooth devices come within range of each other, they immediately begin a series of negotiations to determine if they have data to share or need to make a connection, and then they form a small network known as a piconet or a personal area network (PAN for short). Therefore, if you have a Bluetooth-enabled notebook and you want to send data to a Bluetooth printer, the connection is automatically made without using cables.
Bluetooth devices depend on a set of rules, or profiles, to communicate with each other – else you’d have headsets trying to communicate with printers, for example. Typical profiles include a Serial Port Profile for connecting to devices such as printers and scanners; an Object Push Profile for moving data between devices; a Synchronization Profile for PDA sync operations; a Fax Profile, which allows a PC to use a cell phone as a wireless fax modem; a Headset Profile; and more. Version 1.1 of the Bluetooth standard has 13 profiles so far.
Replacing the Wireless LAN?
So why isn’t Bluetooth used to run wireless networks? In a word, range. Bluetooth devices can communicate within a 30 to 40 foot range before the radio signal begins to deteriorate. For this reason, Bluetooth does not compete with other popular wireless networking standards (such as 802.11a and 802.11b), although it is ideal for short-hop communications.
For instance, cell phone manufacturers are shipping Bluetooth-enabled phones for use with wireless, hands-free headsets and voice-activated car phone kits. Many PC manufacturers are offering Bluetooth wireless radios as an option on their desktops and notebooks, so those systems can exchange data with Bluetooth-enabled PDAs, among other devices. Bluetooth printers, keyboards and mice are available as well, so you can theoretically connect an entire small office without any cables. Plus, there are add-in adapters available to make your existing desktop, notebook, PDA or printer Bluetooth-ready. And Sony even offers a mini-DV camcorder with a Bluetooth transceiver built in, so you can email still photos or video clips without connecting to a computer.
At this point, Bluetooth is still considered an emerging technology that may or may not take hold. Bluetooth products are slow in coming to market, mainly because there just aren’t many compatible devices out there yet. But, with some of the leading PC, cell phone and peripheral manufacturers on board, it’s hard to believe this will remain the case for long.
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