Does using Bluetooth ever drive you crazy with dropped connections to your desktop mouse, or with pairing and sound-quality problems on your smartphone? If so, you're not alone.

As a wireless connectivity technology, Bluetooth is designed to be relatively easy to use, and typically it requires little more than entering a four-digit PIN to instantly pair, say, a keyboard with your iPad.

And yet, for all its purported simplicity, online forums are full of users complaining about Bluetooth problems--whether it's iPhone owners looking to pair a novelty handset or a first-time laptop user just looking to turn Bluetooth on. "I cannot use Bluetooth. I don’t know what is wrong with my laptop but this problem is frustrating for me," said one user in the TechArena forum. Another user, on Tech Support Forum, wrote: "I KNOW I have bluetooth, I checked BIOS and it says it is enabled... so lost right now, and a touch frustrated."

Bluetooth mysteries appear to fall into several different categories. Some are as simple as not knowing how to turn on a Bluetooth chip in your PC or smartphone. Others include figuring out which software driver to download for your PC, or understanding how to deal with signal drops on a headset. A more problematic situation is when Bluetooth capability breaks down, through no fault of the user.

In early 2011, for example, many Windows Phone 7 users started complaining about Bluetooth pairing and audio-quality issues; Microsoft soon said it was investigating the issue. In October, a number of Mac owners complained about Bluetooth pairing problems after upgrading to Mac OS X 10.7.2 Lion. "I am having trouble with my bluetooth mouse after upgrading to 10.7.2," wrote a frustrated Apple forum user going by the aptly chosen online moniker "arrrrrrgh." Others told similar stories of being unable to use Bluetooth. These problems have since been resolved.

Bluetooth is by far the most popular short-range wireless technology for device-to-device data transfers. And it's everywhere--in smartphones, laptops, cameras, televisions, car dashboards, and home audio systems. You can use it to stream music wirelessly from your PC to a Bluetooth-enabled smartphone or MP3 player. Many people use Bluetooth for hands-free calling, and Bluetooth headphones are also a popular choice for listening to music on the go.

The technology ships in more than 19 million devices every week, according to the Bluetooth Special Interest Group, a trade association dedicated to advancing Bluetooth technology. The Bluetooth SIG has more than 15,000 member companies, including major consumer technology firms such as Apple, Intel, Lenovo, Microsoft, Nokia, and Toshiba.

The most recent version of Bluetooth, version 4.0, includes new low-energy protocols for transmitting data from medical devices such as glucose monitors and stethoscopes, and other low-powered gadgets like pedometers and watches. Bluetooth 4.0 also includes the capabilities of its predecessor, 3.0 + HS, which improved Bluetooth's data-transfer capabilities thanks to its ability to pair two devices and then switch large data loads from Bluetooth to the 802.11 wireless standard, the same standard used for Wi-Fi connectivity.

Next: Bluetooth Alternatives; How to Solve Bluetooth Problems