The Apple iPod originally used a FireWire connection to a computer. This connection was used to update songs. The same connection was also used to recharge the battery. The Appel iPod battery was also designed to be charged with a power adapter. The power adapter was shipped with the first four generation models.
With the third generation, the apple iPod models introduced a dock connector. The connector allowed a FireWire or USB cable to be connected into the Apple iPod. This connector was designed to provide a better compatibility with a computer. This is because most of them were not designed with a FireWire port at that time.
The dock connector for the Apple iPod also makes it possible to easily exchange data and sound files with an iPod. It can also be used to power up an iPod. This also helped a lot to ultimately create a large market of accessories that are manufactured by various third party companies like, Belkin and Griffin.
The second generation iPod Shuffle was designed with a single 3.5 mm jack that is meant to act like a headphone jack as well as a data port for the dock.
Eventually Apple began manufacturing the iPod models with USB cables instead of a FireWire. However if somebody wanted a Fire wire than it is easily available separately. With the first generation Apple iPod Nano and the fifth generation Apple iPod Classic, the company stopped the use of FireWire for the purpose of data transfer. After that the company made a full transition to USB 2.0. This was an attempt to reduce the cost and form factor. This changed the whole scenario with the Fire wire now left for just recharging the iPod.
As of now both the USB cable and the Fire wire for the Apple iPod is easily available in the market.
