What is Bluetooth®?

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 Signal Strength Range
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.

How Do I Choose the Best Bluetooth® Audio Transceiver?

A Bluetooth® audio transceiver is typically a small device that allows you to play digital audio from any number of devices through a stereo system. Many products with different designs and features offer users and audio enthusiasts the ability to transmit audio signals wirelessly from small devices to larger ones, such as home or car stereo systems. These components can vary in terms of their individual capacities, signal strengths, and hardware capabilities. Compatibility with multiple digital formats and technology products requires an assessment of the specifications of your devices and your audio needs. Features to consider when selecting the best Bluetooth® audio transceiver include size, design, quality, range, and power consumption.

Quality of construction as well as user reviews and reports may influence your choice. Compatibility with intended devices may factor in, as well as compromises in audio fidelity and signal bit rates versus degradation of high-end audio in the compression process within the Bluetooth® bandwidth. Whether you are drawn by vivid colors or technical power, there is likely a Bluetooth® audio transceiver designed expressly for your purposes and within your price range.


Typically a small handheld dongle, or desktop device, a Bluetooth® audio transceiver may be fitted with various ports or jacks for compatibility with equipment such as laptop computers, cell phones, or stereo systems. Digital audio formats such as Moving Picture Experts Group Audio Layer 3, or MP3, MPEG-4, compact disc, or other digital signals are transmitted between other digital media devices; compatibility between devices is fully preserved, while quality of compression coding or interference can sometimes degrade the signal. These signals may be transmitted through a single transceiver to one or more media players located around a home. As long as the Bluetooth® device is within range, wireless signals can be broadcast conveniently from a player to a separate transceiver located elsewhere, and into a speaker set-up, without any use of wires or cords. It should be noted that digital formats usually compress audio, resulting in slightly reduced quality through a stereo system, compared to playing from a compact disc directly.

Generally, a transceiver is a device that transmits and receives digital signals, such as those from a compact disc or a computer file. Bluetooth® audio transceiver devices combine the capabilities of dedicated receivers or transmitters, so it's important to determine which type you specifically need. Furthermore, devices might be limited in how many signals they can process at one time. Consider how many other people may want to use the device at the same time, where they may be located, and your combined bandwidth needs.

Households might benefit from a transceiver capable of processing multiple streams while preserving audio quality against interference dropouts. These units are typically capable of converting digital and analog signals for compatibility with more traditional equipment, as well as the latest mobile devices. They may be subject to dynamic range limitations from signal amplifications and receiver outputs — that is, the power limitations of each component.

The Bluetooth® wireless protocol permits simultaneous broadcasting by separating signals throughout available channels. Some equipment may feature more powerful antennas, audio cables, and alternating current (AC) adapters in order to better service residential needs. Other handheld or remote devices might feature electronic readouts, player controls, or cigarette lighter jacks suitable for use in a vehicle. Wireless transmission can quickly absorb battery power, so including alternative power sources for remote uses may serve your needs.

Devices may be designed for use with portable or console video gaming equipment, personal digital assistants, and televisions. Certain types are limited to battery power, while others come with their own docking stations or are able to plug into a computer Universal Serial Bus (USB) port. Consider the compatibility issues with your preferred equipment and audio environment in order to best select a device that can accommodate your desired set-up.

What Are Different Types of Bluetooth® Accessories?

Bluetooth® technology refers to a wireless technology used for short-distance transmission of voice and data. Bluetooth® accessories include the traditional hands-free cell phone headset devices that provide connections to a car's audio system, computers, printers, or cameras. The catch is that connecting the devices requires compatible Bluetooth® technology, often the same version. Additionally, the devices must be within close proximity of each other — up to about 300 feet (91.44 m).

Capabilities of Bluetooth® cell phone headsets can greatly vary in terms of performance and features. Basic headset features include answering or rejecting calls. Others can be programmed so they can be controlled with voice commands, such as calling a spouse's phone number. Clear sound is also important with headsets. Some of the higher-end headsets have features to cancel out background noise.

Later-model cars may come wired for Bluetooth®, allowing drivers to use a device to access the car's audio system for hands-free cell phone use. If not, a car kit accessory may be able to provide the same access. This is considered a safety feature, as traffic accidents can happen when motorists are distracted by trying to dial a cell phone. Depending on the locale, some laws that require the use of headsets while driving and talking on a cell phone.


Bluetooth® accessories can also be used to stream music between Bluetooth®-enabled devices, such as MP3 music players. This allows users to listen to radio or music tracks while using wireless headsets. Wireless speakers allow the streaming of audio files from a desktop or laptop computer. This also prevents listeners from being tethered to a computer via wired ear buds or headphones. Likewise, a home stereo adapter can eliminate the need for wires used to connect stereo components; this works by using the MP3 player on a Bluetooth® phone to play music over a home stereo.

One of the Bluetooth® accessories that can be useful everyday is an adapter that links a computer to other computer-related devices, such as a mouse or printer. It can also be used to transfer data from a laptop computer to a desktop computer. Yet another capability of Bluetooth® technology allows a cell phone to connect to the Internet. When this happens, encryption is used to ensure privacy and secure the data.

One of the more unusual Bluetooth® accessories is a device that connects to the wrist to monitor sleep patterns, called the WakeMate. The data is analyzed so that another device, such as a cell phone, that can wake up the sleeper at an optimal time. It even comes with instructions on how to get a good night's sleep.

How Do I Choose the Best Stereo Bluetooth® Headset?

Stereo Bluetooth® headsets have become essential gizmos for many people who are constantly on the go. Being able to receive phone calls hands-free, with the added functionality of listening to high-quality music from one’s stereo system, digital media player or computer in stereo sound, has made it a must-have gadget for savvy professionals and many others. There are plenty of models out there to suit every budget, and every headset has its own advantages and disadvantages. To choose the best stereo Bluetooth® headset, some things to consider are comfort, compatibility, battery life, sound quality and ease of use.

There’s no point investing in a fantastic headset if it is always falling out of your ears. These headsets come either as earbud-style units that plug into the ears or headphone-style units that have a band connecting the earpieces. You’ll probably be wearing your headset for long periods of time, so check to see whether it feels awkward or sits lightly on your ears. Also consider where you might be using it the most. For example, if you plan to use it during your gym workouts or while jogging, then you’ll probably need a very lightweight model that is also resistant to sweat.


Check to see whether your stereo Bluetooth® headset is compatible with your cell phone by taking a look at the compatibility lists provided by the manufacturer. Ensure that your cell phone supports two important types of profiles: the Advanced Audio Distribution Profile (A2DP), which makes it possible to stream high-quality audio wirelessly in stereo sound via Bluetooth® signals; and the Audio/Video Remote Control Profile (AVRCP), which allows you to control your music wirelessly via your headset. Also take a look a the number of devices that are compatible with your headset, because that gives you more options.

Another thing to consider is battery life. Most of these headsets average about five to 10 hours of talking time, with some hardier models delivering about 12 hours. Read through some reviews to see how the manufacturer’s claims of battery life compare with usesr’ experiences before making your choice.

Sound quality is an important consideration when choosing a stereo Bluetooth® headset. Check to see whether the headset delivers sound at a good volume, which can be important when you are in a noisy environment. Make sure that turning up the volume does not cause the sound quality to decrease. You also might check whether the headset provides anough base or can be adjusted to increase or decrease the bass.

If you are fiddling around with your headset all of the time because the controls are too complicated or to difficult to locate, then its going to be hard to use long-term. Check to see whether the microphone is close to your mouth when you wear your headset, or it might sound like you are mumbling. Confirm whether the model that you are considering includes features that you’ll use often, such as track-skipping or volume control.

Check with your friends and read up on as many reviews as you can find on the performance of the stereo Bluetooth® headset that you are considering. People who have used a headset will be able to tell you whether it is a hardy model that offers consistent sound quality and whether calls come through clearly, without any distortion or noise. Other users also might be able to tell you whether the manufacturer provides top-notch customer support

How Do I Choose the Best Car Stereo with Bluetooth®?

There are several in-dash car stereo systems on the market with Bluetooth® capabilities, allowing hands-free calling via a compatible cell phone while driving. Choosing the best system means making a few decisions regarding the myriad options available. Music streaming ability, touch screen ease of use and number of AV inputs and outputs are all options that should be considered when shopping for a car stereo with Bluetooth®.

Older car stereo units require add-on external modules to use with Bluetooth®, but there are a number of new models of car stereo with Bluetooth® built in. Not only do these systems offer hands-free calling, but they have many other options, as well. While most have built-in AM/FM radios and CD players, others also are able to integrate music stored on MP3 players. A few support advance audio distribution profile (A2DP) audio streaming, allowing the user to stream music from other Bluetooth® mobile devices. Others even allow one to watch DVDs.

The user interface may be either touchpad or touch screen, with the latter seeming to offer the most convenience. The size of the screen may make a difference with ease of use, and visibility is sometimes a concern, because the screen may be either too bright or not bright enough. The size and visibility of the screen is particularly important if the user plans to watch video on the device. Some touch screens are customizable, while others are not.


When using a car stereo with Bluetooth®, it is important to consider safety as well as convenience. A straightforward, easily navigable menu display is a must, and a consumer may wish to have the touch screen display caller ID and imported contacts information for hands-free calling. Reading professional reviews about these products as well as user reviews on the Internet is a good way to ascertain which devices offer these options. Some car stereo with Bluetooth® systems come with microphones that are either behind the faceplate or too small to convey adequate sound quality, so user reviews will be especially useful in that regard.

Other enticing options include units that have multiple auxiliary inputs for connecting portable devices such as laptops and outputs that allow the user to attach subwoofers and amplifiers. The location of these jacks differ, and some systems place one or two in the front for convenience. Some types of car stereo with Bluetooth® also come ready to accept high-definition and satellite radio services, if desired. Those who prefer using knobs to control volume and selections will be able to find these on some of these car stereos, but not all offer this option.

Do Bluetooth® Headsets Cause Cancer?

It is difficult to imagine that you could suffer health problems by using a mobile phone or headset. Yet health experts and concerned consumers have raised serious questions about the possible effects of mobile devices, including fears that they might cause cancer. Conclusive evidence has never been discovered, but many experts suggest that the microwave emissions from phones and Bluetooth® headsets might carry some risk of cancer or other health problems.

Since the invention of cell-phone technology, studies have been conducted to see whether they pose health risks. The concern is sensible, given that cell phones are low-powered microwave emitters, and some microwaves have been shown to pose health risks. Experts and consumers worry that keeping a microwave emitting device close to your head and your brain could put you at risk for brain cancer or other damage. The concern is sometimes greater in regard to Bluetooth® headsets, as the device is placed inside your ear and therefore even closer to your brain.


Studies have had extremely conflicting results. Some early examinations of the effects of cell phones on cells show significant damage, while others show none at all. Additionally, some people may suffer from hypersensitivity to the microwave radio frequencies, causing them to get headaches just from turning a phone on or being in a room with someone on a phone or headset. According to the United States Food and Drug Administration, the US Federal Communications Commission, and the United Kingdom National Radiological Protection Board, all available scientific research shows that mobile devices are safe, but further research is necessary.

Bluetooth® headsets are a fairly new technology, so in-depth studies are yet to be completed about cancer risks. While many earpiece devices actually emit lower levels of radiation than cell phones, the earpiece does put the source of power closer to your brain. Public opinion seems to be divided fairly equally between those who believe Bluetooth® headsets riskier than cell phones, those who believe they are safer, and a large group that thinks the question is ridiculous because the radiation levels are so low to begin with.

Mobile phone technology has only been widely used since the mid-1990s. Because Bluetooth® headsets are such a new feature, it is impossible to get data about long-term effects of consistent exposure. Some people suggest that within twenty years, better studies will be available, as the first generation to grow up using cell phones and head sets will effectively be guinea pigs for long-term effects. If you are truly concerned about the microwave emissions from your cell phone, skip Bluetooth® headsets and simply use the speaker-phone option that is standard on most phones. Although scientific research has not provided clear answers as to whether Bluetooth® headsets can cause cancer, this may be an area where you feel it is better to be safe than sorry.

What is a Bluetooth® Transmitter?

In the mid-900s, the Danish king Harald Bluetooth united Denmark and part of Norway into one kingdom. In the late 20th century, Swedish engineers at Ericsson developed Bluetooth® transmission, a wireless technology that can unite different electronic devices regardless of their type, manufacturer, or operating system. Using low-power radio waves, a Bluetooth® transmitter can transmit signals from a computer to a stereo system, from a cell phone to a printer, or from an Apple to a PC.

Remote controls use infrared signals to send information from the remote control to a device like the TV or DVD player. For a remote control to work, however, it must be pointed directly at the TV. With Bluetooth® wireless transmitters, devices within 30 feet (10 m) of each other can communicate, even through walls and around corners. This is because a Bluetooth® transmitter uses 2.45 GHz radio waves to transmit signals, the same frequency used for baby monitors and newer cordless phones.


When one Bluetooth® transmitter senses another one, it automatically establishes a small wireless network, called a piconet, that works as long as the transmitter and receiver are within 30 feet (10 m) of one another. A user might, for example, walk into his house, and his cell phone calls could automatically be forwarded to his cordless land line. As he passes his computer, his emails could be downloaded into his cell phone or PDA, then he can send downloaded music to his stereo and photos from his digital camera to his daughter’s phone. Bluetooth® wireless technology eliminates the need for a different cord to allow networking between different devices.

Because the 2.45 GHz frequency is also used for other devices in the home, engineers had to work out a way to prevent interference. They needed to prevent things like a cell phone accidentally causing a garage door to open. To accomplish this, a Bluetooth® transmitter uses a very weak signal, just about one milliwatt.

Additionally, a single Bluetooth® transmitter can communicate with up to eight other devices at the same time, without interference. This is done with what is called “spread spectrum frequency hopping.” Since the 2.45 GHz frequency actually encompasses the range between 2.402 GHz and 2.480 GHz, Bluetooth® can hop between 79 different randomly chosen frequencies at a rate of 1,600 changes per second. This makes it unlikely that any two devices will be using the exact same frequency at the same time, and if they are, the interference will last no longer than a few milliseconds.