Bluetooth wireless communications technology - dongles
The word “dongle” is a rather odd sounding term, and in fact seems to be a word that couuldn't possibly have any serious meaning. While it may sound silly, the term actually describes a small computer component, such as a USB Flash Drive 
Dongle As Copy Protection
The original dongle was a small piece of computer hardware that plugged into a place on the computer and was required before certain software would run. Since the software would require the necessary piece of hardware to run, this made it harder, at least in theory, to pirate a program. This concept was most popular with more expensive programs, such as Computer-Aided Design (CAD) packages, which are used by engineers and architects to create designs. While this sort of use of dongles was popular with software companies, most computer users were less than happy with such protection methods, since use of the software was dependent on a piece of hardware that could easily break or be misplaced.
Laptop Dongles
It wasn’t until laptops gained in popularity that dongles began their evolution into the mobility enhancing devices that blue tooth dongles are today. Laptop dongles were little cords that plugged into the ultra-thin modem and network cards that went in PCMCIA slots on one end, and had a jack for phone and network cables. This was to allow laptops to access mobile communications at a time when hardware manufacturers were not yet capable of fitting the jacks in the laptops. This was the beginning of the use of dongles in enhancing mobility. The cables tended to be fragile, so they rarely used much anymore, having been replaced by wireless technology and laptops with the needed jacks built in.
USB And Blue Tooth Dongles
With the advent of USB technology to create plug and play devices that can be plugged in and removed from the computer while it is on, dongles have evolved into more useful items. One of the more common dongles in use today are USB memory devices, which contain flash memory and can be used like a mini hard drive, plugging into a USB slot rather than a disk drive.
Finally, a blue tooth dongle looks similar to a USB drive, but rather than store data, it turns a computer into a wireless blue tooth device. The big advantage to a blue tooth dongle is that it ensures that any computer with a USB slot to plug into will become a device capable of connecting wirelessly to blue tooth enabled printers, cameras, phones, PDA's, keyboards, and other devices. The small size of a blue tooth dongle - about the size of a pack of gum - makes it easily portable. It is the culmination of decades of evolution, and anyone who has made use of these handy little devices would certainly agree that dongles are indeed useful things to have around.
Mustek MBT-D120 Bluetooth(tm) Dongle