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Bluetooth Basics


Invisible radio waves traveling through the air can make your life more fun and productive. Introduced in the 1990s, Bluetooth technology helps people move about the world freely and use electronic devices without plugging them into anything. Buy a Bluetooth headset, for example, and hold a phone conversation with someone while your phone sits in your pocket or purse. Bluetooth also allows photo enthusiasts to transmit images from their cameras through the air into their PCs. When you?re ready to untangle your computer life, sever the cord between your printer, mouse and keyboard by replacing these peripherals with their Bluetooth counterparts. Understanding a few basic principles can help you use your Bluetooth devices safely and efficiently.

    Radio Wave Communication

        Bluetooth allows two or more electronic devices to communicate via radio waves. Before Bluetooth, computers and other devices could do that using technologies such as infrared radiation. This technology has limitations because both devices must be able to see each other?s sensors. Bluetooth solves this problem by enabling devices to exchange information using low frequency radio waves. The type of information that they trade depends on the application. While a camera might send image information to another camera, a Bluetooth music player can send music from a stereo to a speaker in another room. This is possible because Bluetooth signals can travel through walls.
    Bluetooth Versions

        Bluetooth evolves over time and acquires higher version numbers and the technology improves. In 2007, for instance, CNN Money looked forward to the upcoming 2.1 Bluetooth version. That version promised to make it easier for devices to establish connections. Setting up these connections was not a simple task using version 2.0. About a billion Bluetooth devices existed when CNN wrote the article. Bluetooth version 3.0 came in 2009 and made Bluetooth even better. (See Reference 1 re this info)
    Technical Details

        Bluetooth devices consist of hardware components, microchips, electronic circuits and software that make the process work. Every moment, radio waves surround you as they journey from one location to another. Some of these have high frequencies and others have lower ones. When one Bluetooth device connects to another, a miniature low frequency network called a piconet forms. You can purchase Bluetooth devices that use low, medium or high power levels. A device's power level determines its communication range. You only need a low power device operating at 1 miliwatt If you wear a headset that talks to a nearby phone. You need a higher-powered device operating at 100 milliwatts if you need your device to communicate with another one up to 300 feet away.

        Your Bluetooth device is useless unless other devices can find it. You have the option to put your device into a ?discoverable? mode that causes it to listen and wait for other devices within range to "speak" to it. Discovery takes place on one of the device?s special channels when another Bluetooth device is near. Devices beyond your device?s range will not be able to locate yours.
    Frequency Hopping

        Bluetooth operates in the same 2.4 gigahertz frequency band reserved for industrial, scientific and medical devices. All these devices operating on the same frequency can crowd that frequency range if not for Bluetooth?s frequency hopping trick. This is a technique where all devices in a piconet shift their frequencies 1600 times per second. Because of this synchronized frequency dance, Bluetooth devices in a piconet can share information in a crowded room without interfering with other Bluetooth devices not on the piconet. The National Institute of Standards and Technology reports that frequency hopping also helps reduce transmission errors.

        After one Bluetooth device discovers another, pairing must take place to establish a connection. This process allows the devices to authenticate themselves and exchange passwords. This ensures that both devices are connected. The pairing process, which varies by device, requires little user intervention because the device's software handles the complex handshaking task. After switching your device in to discoverable mode, you will be given a list of available Bluetooth devices. You choose the device you want to pair with, and then enter the appropriate password if one is required. Consult your device's owner?s manual if you need assistance performing this task. It will list the device's default password if one exists and offer additional details if needed.
    Bluetooth Vulnerabilities

        The National Institute of Standards and Technology (NIST) lists 17 security vulnerabilities that Bluetooth device makers and organizations using those devices should address. Line item number 17, for example, suggests that devices encrypt all transmissions to help protect them from others who may wish to intercept them. Bluetooth specifications define four possible security modes that devices can use. Devices using Security Mode 1 have no security, while Mode 2 has a security manager that determines the services that other devices can access. Modes 2 through 4 use encryption, but the NIST considers Security Mode 3 the strongest; it uses authentication and encryption before devices establish a link. All Bluetooth devices support one or more of these modes. The mode your device supports depends on the Bluetooth version it uses. Consult your device's documentation if you need this information.
    Security Tips

        Bluetooth devices are subject to the same types of network attacks that plague regular wireless networks; attackers can gain access to devices that owners do now secure properly. The NIST recommends using the strongest security mode for your device. If attackers discover your Bluetooth device, they can send it messages and attempt to steal its data. They can also infect your device with viruses that can spread to other devices connected to yours. The U.S. Computer Emergency Readiness Team recommends disabling Bluetooth when you are not using it. They also suggest taking your device out of discoverable mode after pairing it with another device. You should also change your new Bluetooth device?s default password after purchasing it.
    Interesting Bluetooth Devices

        Creative minds have discovered unique ways to harness the power of Bluetooth radio waves. VKB?s laser keyboard for mobile devices, for instance, allows you to project a virtual keyboard onto a flat surface and type text that winds up in your device. Maxing out the Bluetooth range, the HIOD One communication device by Hiod allows cyclists wearing headphones to chat with other cyclists up to 1,312 feet away. The device also lets you listen to music as you cycle. One way to impress your friends is to make a robotic ball roll around the floor using your cell phone. Sphero, distributed by Orbotix, takes Bluetooth to a new level by enabling mobile devices to broadcast radio waves that control the round robot.
    Bluetooth 4.0

        Bluetooth 4.0, the latest version as of February 2012, opens the door to an exciting line of new low-powered Bluetooth devices. Also known as Bluetooth Smart, Version 4.0 allows developers to create smaller devices that have longer ranges. Because the devices don?t use as much power, they can function for months or years without anyone changing their batteries. Bluetooth.com, the official Bluetooth information website, reports that the first Bluetooth 4.0 devices were beginning to reach the market as of February 2012. The site also notes that almost all new smartphones will use this emerging technology by the end of 2012.

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