How Bluetooth Car Stereos Work

Now that we've got a handle on Bluetooth 101, let's see what it can do in a stereo. Bluetooth car stereos are commonly integrated with Bluetooth-enabled cell phones, and when the two devices are within range of each other, they can communicate in a number of interesting ways. Depending on the particular models in use, it may be possible to make and receive calls without even pulling out your phone or pushing a single button. You can even hear the calls through the vehicle's speakers. Other models may require a few button-pushes, but usually with more ease than plodding through cell phone menus. You may also be able to view other information such as the phonebook, incoming calls and call status on the stereo panel. When the phone rings, the speakers will automatically turn down the volume on any music or movies that are playing while you chat on the phone and resume when the call is over.

Some Bluetooth car stereos can store your phone's entire address book and other contact information; others have built-in phones which copy all the information off your phone's SIM card and take over the functions for calling. Your cell phone is disconnected from the piconet, not only saving its battery power but also providing a stronger connection.

These innovations come almost as much out of necessity as convenience -- at least for people who can't stand being in the car without making a quick phone call. Many places now enforce laws limiting the use of cell phones while driving, and Bluetooth car stereos are one way to bridge the middle ground.

Besides augmenting your ability to connect with the outside world through phone calls, Bluetooth car stereos can also enhance the environment inside a vehicle. Transmitters can be used to stream music from iPods, MP3 players and satellite radio straight into the stereo without creating a mess of tangled cords. Some car stereos can display video on full-color LCD displays, although this usually isn't an option when the car is moving. If you have some passengers in the back who could use a movie to settle down, lots of Bluetooth-enabled car stereos also come with the hookups needed to turn your vehicle into a mobile entertainment center. Connections for other devices like GPS navigators and USB flash drives are among other common fixtures.

And with each passing year, the technology grows and evolves. Comparing Bluetooth-enabled car stereos to cassette-enabled car stereos already seems like a throwback to the Middle Ages, so who knows what the future has in store.

If all this talk about Bluetooth car stereos has you hooked, on the next page, you can read about some of the considerations you'll want to make before you head down to the electronics store.

­Many new vehicles come with Bluetooth-enabled stereos straight from the factory, but you can also purchase specific or universal adapters if your car isn't one of them. The universal adapters are more likely to have limited functions, while the stereo-specific ones offer a broader range of features. Stereos that have Bluetooth built in tend to be the most advanced, as we read on the last page, often with full phone control, streaming music capabilities and more.

There are a couple of considerations you'll want to keep in mind, though. Some cars have stereos that are more challenging to substitute out than others. For example, if your vehicle has a climate control system or other key feature linked through the stereo, you might want to reconsider yanking it out. Those who are slightly less tech-savvy should also make sure the Bluetooth car stereo they have their eye on is one they can actually operate efficiently. Hands-free capabilities aren't much of a benefit if you spend all your time fiddling with the controls trying to make everything work properly.

On a similar note, it's also a good idea to thoroughly check the features on your Bluetooth car stereo to make sure it has all the functions you want. Nothing worse than taking an expensive new acquisition out for a test drive only to find it only gets half the job done. Although Bluetooth is a universal technology, there can be some hang-ups if you try using newer Bluetooth devices with older ones, so it's smart to verify everything in your electronics landscape will get along before making any purchases. Security might also be an issue. Many models feature some modicum of theft protection, whether the ability to remove the face of the stereo or flip it around to make it more low key.

One concern with using Bluetooth technology is the possibility of being hacked. If you'll recall from the first page of this article, Bluetooth operates on radio waves, and hackers can use this to their advantage to interfere remotely in a number of different ways. They can potentially steal passwords, and they can also reportedly communicate with a passing Bluetooth network.

This particular hack, known as the Car Whisperer, allows someone to listen in to a Bluetooth network set in a vehicle -- whether a phone call or a simple conversation between driver and passenger -- and even participate in that conversation if they choose. A nonprofit organization called the Trifinite Group tested the Car Whisperer phenomenon, and they proved that unprotected devices are at risk should a hacker be in the vicinity -- although with some simple equipment, the vicinity can cover a much larger range than Bluetooth networks traditionally encompass. Plus, if the hacker was following his or her unknowing target in a vehicle, the eavesdropping could become even more serious. Strong password encryption and other security measures are steps manufacturers and users can take to help diffuse the threat.

On the next page, you'll find links related to Bluetooth, Blackberry and other phone technologies