With the iPhone 4 Dock, you get easy access to a dock connector port for syncing or charging, and an audio line out port for connecting to powered speakers via an optional audio cable. The iPhone 4 Dock also works with the USB Power Adapter.Charge and sync your iPhone 4 or iPhone 4S with the iPhone 4 Dock. Your iPhone sits upright in the dock as it syncs or charges, so it’s perfect for a desk or countertop. It features a convenient audio line out port that connects to powered speakers. It supports other iPhone 4 accessories, such as the USB Power Adapter. You can even conduct speakerphone calls with your iPhone in its dock.Here are some ways you can use the iPhone 4 Dock:- Connect the dock to your computer with the USB cable included with your iPhone to sync iPhone and charge its battery.- Connect the dock to an electrical outlet using the Apple USB Power Adapter (included with your iPhone) to charge the battery.- Place your iPhone in the dock and enjoy clear audio during speakerphone calls.