Synchronize and charge your Samsung Galaxy S IV with RND Power Solutions Deluxe Cradle / Desktop Dock Station. The USB Desktop Dock holds it at a comfortable reading angle. Charge and synchronize data simultaneously when connected to your PC using the USB micro cable (included) or charge your smartphone using the AC power adapter. RND Power Solutions Deluxe Desktop dock/cradle has a power protection circuit so it does not burn out your batteries. It will fit your phone with a case by removing the middle insert. No case no problem the middle insert is included that fits your phone perfectly. To place your phone into dock mode turn the switch on the back towards the speaker. Samsung clock widget will pop up. You can connect the dock to an external speaker system using an aux audio cable. You will need to go to the phone settings then accessory then check speaker out in dock mode. Turn your phone volume up to the max setting and your speaker will control the volume. Make sure on the back of the cradle the switch is towards the speaker icon. Data cable is for connecting to the computer for syncing. The cable will also charge like standard cables in the market. If you want to sync you need to be out of dock mode by toggling the switch on the back of the cradle to the sync icon. The charging only cable uses new technology built in the Samsung phones. Basically it will charge your phone 30% faster than normal cables. This cable you cannot sync and is only built for charging. NOTE: A case thicker than 1mm may not fit. For example the majority of double layer cases will not fit. RND Accessories does carry cases that are compatible. PLEASE feel free to contact us if you have any questions. We will be happy to assist you.