Beyond those ubiquitous "thumb" drives, you can use USB to connect to DVD and CD drives and burners, external floppy drives, and flash memory readers, some of which claim support for as many as 12 memory card formats. Most printers sold today have only a USB connection. But you can also buy parallel-to-USB converters for older printers. These adapters are great for those older laser or other high-end printers and can be found for $13 to $40, which is a lot cheaper than a new printer. For older equipment that uses the DB-9 serial, you can buy USB adapters for $20.
You can also use USB to plug in keyboards and mice (especially great for laptops); in fact, some newer computers rely on the USB ports for these input devices. There are adapters that will convert the PS2 mice and keyboards to USB. Then there is the SVGA-to-USB adapter that can be used for running a larger or remote monitor (up to 1024x768 resolution) or second screen—great for those display-hog programs. These are available online for $90-$100 (second monitor sold separately).
If you do audio recording, handy USB devices range from simple input jacks to some pretty cool mixers with multiple inputs and productivity software for audio editing, multi-tracking, and other audio manipulation. Some of the big names in audio are producing these: Tascam (TEAC), M-Audio (Avid), Behringer, Alesis, and others, have all types of devices to turn your computer or laptop into a high-quality recording studio. The smaller units are great for recording and editing programming on the road for podcasting. These can range from under $100 to the $300-$500 range.
Another new USB-based audio "toy" is an AM/FM receiver ($60) that makes your computer into a TiVo for radio.
Also in the audio family, a new USB microphone just caught my eye. Called the Snowball (because that's what it looks like), it plugs directly into the USB port of a computer with very good frequency response and great sound-pressure ratings. It works without a mixer because its A/D conversion is in the mic itself. You can plug it in and use your existing audio software (like Sony's Soundforge) to capture the sound. The Snowball, which lists for $140, is manufactured by Blue, a company well-known for its high-end studio mics (for more info, see Gear & Now).
For video, there are a number of USB adapters that allow for capturing and digitizing analog into a computer for NLE editing. Some of the smaller units go for $60 or less, while others offer additional features such as MPEG conversion for a small additional cost (about $80).
Then there are extenders. These adapters allow you to run extended lengths of USB cables for things like accessing a networked printer. These in-line adapters (about $15-$20) can add 80' to the transmission distance. For longer runs, there are $75 USB-to-CAT5 adapters that can extend that run to 300' and are extremely useful for buildings that are already pre-wired for CAT5.
Need to share a USB device between two computers? Pick up a switch or share a switch. Most are integrated with a hub for multiple devices, and allow you to access a printer or I/O device from two computers without swapping cables.
Need to move or back up files between computers? There is a double-ended (A-to-A) USB cable that allows you go join two computers to move files back and forth. It's great for backing up a laptop, and for $10 it's a real bargain. A USB 1.1-compliant cable, it can transfer up to 4Mbps.
Then there are devices that use a computer's USB port for power and are not real USB devices. These include keyboard lights ($10-$12), handy for doing laptop work at night; and a laptop "cooler," an aluminum-encased base that houses twin fans that your laptop sits on to keep it cool for extended use. The fans are USB powered, list for about $30, and are worth every penny.
There are also dual-use cards that have both USB 2.0 and IEEE-1394 (FireWire) ports for about $35, for those who are running out of card slots and need both types of ports.
As you can see, this popular computer port has many uses and has become the I/O port of choice for a range of applications with both manufacturers and users alike. I'll bet that by the time this column hits the newsstand, a few new products will be added to this list.
A note on USB: USB 2.0 provides data transfers as fast as 480Mbps and links up to 127 devices. USB 2.0 is also backwards compatible with the older USB 1.1, which has a maximum transfer rate of only 12Mbps. How does USB allow you to communicate with so many devices? Through dynamic addressing. Each device has an internal address, but when you install the device, you give it a name, which gets associated with the internal address. So you can have ten printers connected and talk to each one individually, even though they may be the same make and model. The USB ports also provide power through the cable/connector, eliminating the need for an external power supply for many products. There is a limit on this power supply, however, and if you plan to use your USB port to power a number of devices, you may need a hub or power booster.