When the iPod switched its connector from a FireWire port to the proprietary 30-pin Dock Connector, several new compatibility and hardware features became available. Because the Dock Connector handled data, sound, and charging capabilities, a variety of connection options were available.
The iPod Dock allowed a connected iPod to simultaneously charge, send sound to an external stereo system through a line-out port in the back, and respond to commands from an Apple Remote control device.
The iPod Generation 3 was available in three sizes: 15 GB, 20 GB, or 40 GB on a 4200 RPM ATA-66 hard drive capable of storing 3700, 5000, or 10,000 songs. It used a 2-inch (diagonal) monochrome LCD display with blue-white LED backlight in a case with an “iBook white” front and a polished stainless steel back.
This iPod was thinner, lighter, had a more rounded case design, and introduced the idea of an iPod dock for easy connection to a computer or stereo. The buttons were changed to solid-state (instead of the earlier physical buttons) and moved from around the click wheel to a row above the click wheel.