Nearly every computer has to connect to a peripheral, or in some cases, 19 peripherals. There are many different types of connectors and connections. Knowing which cables and sockets your peripherals and PC will help you get what you want. You don't want to spend 4 hours at the store talking to the sales guy to figure it out, do you? In this guide we break down the various flavors of USB and Bluetooth, two of the primary standards for peripheral connectivity.

USB standards

USB (Universal Serial Bus) is the de facto standard for reliable peripheral connections, though there are big trends toward Bluetooth on the desktop, which we will also explore. USB 1.1 is older, but is still widely used. If you run Windows or MAC OS X, USB 1.1 is supported on nearly every desktop and laptop, though the newer machines of the past few years will come with USB 2.0 on board. USB 1.1 is slower than its newer sibling USB 2.0, also referred to as high-speed USB, for that reason. A USB 2.0 connector will most likely be the same physical type as USB 1.1, so it may be hard to tell. The biggest advantage 2.0 has is that it is quite a bit faster, as well as including some improved protocols to enhance the technology. There were versions of USB before 1.0, but this is the one that started to get USB into the popular connectivity limelight. As a comparison, USB 1.0's standard speed is 1.5 megabytes per second. USB 2.0 however has a speed of 480 Mpps. USB 3.0, which is coming to a device near you in 2009 or 2010, will clock in at a whopping speed of 4.8GB, which is the fastest yet.

To fully understand what USB is, and why it works, remember that a serial connection is a sequential transmission of data across the wire, one piece of data at a time, like a popular TV show with a series of episodes that air each week. In contrast, with a parallel connection, all the data is sent across many different lines all at the same time — more like if a TV show released an entire season direct to DVD all at once. The USB specification has many different types of connectors. The most common is the "A" type, the rectangle you've seen on the end of many cables that plug into your PC. The most common types are shown here:

From left to right:

• 8-pin plug (found on video cameras, some digital cameras. There is some debate that this is a standard USB cable, since there are some weird custom cables from manufacturers that have the same shape but use their proprietary wiring, so beware of those when looking for the right cable for your device.)
• Mini-B plug (found on digital cameras, cell phones, portable hard drives and portable media players)
• B-type plug (found on the end that plugs into your printer/scanner/peripheral or KVM switch)
• A-type receptacle (found on the end of extension cables)
• A-type plug (found on almost everything — both 1.1 and 2.0 use this connector extensively)

There are some other interesting implementations of USB, like Wireless USB, which is just starting to peek at us over the horizon. It will no doubt be aimed to challenge the current wireless peripheral standard, Bluetooth. You have probably run into Bluetooth in the cell phone world, and for good reason. Bluetooth is the standard way to connect your hands-free headset to your phone, but it is also used in keyboards, mice, printers, game controllers for Wii and PS3, and plenty of other devices.

Bluetooth standards

Speaking of Bluetooth, it is the most popular specification used in mobile phones because it is perfect for short range wireless communications. Bluetooth made hands-free calling the phenomenon it is today, and its low power usage makes it ideal for very short ranges, like from your ear to your pocket or the car seat. It was developed in 1994 as a way to connect short range devices to each other and solve some of the syncing problems that early Palm devices had using infrared technology. Bluetooth uses an advanced idea called frequency hopping spread spectrum (FHSS) to split up the broadcast of your voice on 75 different radio frequencies (channels if you prefer) on a similar wavelength as is used in Wi-Fi networks in the 2.4GHz range.

Bluetooth (BT) has several versions and several profiles, too many to detail here, some of the most notable being Bluetooth 2.0 + EDR (enhanced data rate) and the stereo Bluetooth profile, also known as A2DP. Bluetooth 2.0, like its USB cousin, basically steps up to the plate with a bigger bat and transmits the ball out of the park a bit faster than previous versions. BT 2.0 with EDR is a profile that specifies the device can serve as a modem via dialup using a mobile phone or PDA. Stereo Bluetooth is an audio profile defining how audio should be handled and transmitted, widely used in phones that don't have a headphone jack, enabling you to connect a Bluetooth headset to listen to your mobile music collection. Without the A2DP audio profile, it is tough to listen to music via the garbled loudspeaker and without declaring your fanaticism for some other horrible 80's band to the whole office. Styx fans, this means you.

USB and Bluetooth are essential technologies that we use every day and work well for how complex they are under the hood. What would life be like without them? To imagine that would be unthinkable. Maybe the machines really are taking over, which is okay with me, as long as I gave them permission to do so. When my printer makes itself a sandwich, then I'll head for the hills. Until then, color me obsessed.

Photo: Courtesy of Wikipedia. The Bluetooth logo is a trademark of Bluetooth SIG, Inc.