1: USB port: Plug the connection into the dock connector port on your iPad, and then attach your digital camera or iPhone (excluded iPhone3G) via an USB cable. Or import photos to iPad through USB flash disk. Besides, the USB port supports external PC keyboard input.                                                                                                               2: SD card port: Plug the connection into the dock connector port on your iPad, and then insert your SD card. 
3: Micro SD card port: Plug the connection into the dock connector port on your iPad, and then insert your Micro SD card.             4:3.5mm DC port: Output video to TV. Plug the connection into the dock connector port on your iPad/ iPhone/ iTouch/ Nano/ Classic; attach TV using the accompanying TV cable.                            5:Mini USB port: Charging & Sync data. Plug the connection into the dock connector port on your iPad/ iPhone/ iTouch/ Nano/ Classic; attach power adaptor or computer using the accompanying Mini USB cable.