The two ports on the bottom are used for a wall charger/car adapter and a variety of extensions including a USB cable. The port on the top is meant for a headset but most users of the phone do not employ a headset because the SPH-N270 is designed with aesthetics in mind.
The lower ports accommodate a wall charger or car adapter, along with multiple expansion options like a USB cable. The upper port is meant for a headset, but since the SPH-N270 prioritizes visual appeal, many users opt not to utilize it.