Microphone
3.5mm Headset Jack
USB/Charger Port
Speaker
Microphone Transmits your voice to the other caller. It's also used for voice-activated functions.
3.5mm Headset Jack Allows you to plug in an optional headset for convenient, hands-free conversations. You can also plug in headphones to listen to music.
USB/Charger Port Allows you to connect the phone and the USB cable for use with the charger adapter, or other compatible accessories.
Speaker Use to listen to audio (e.g., music, videos, sound clips, speakerphone, etc.) from the rear speaker instead of the earpiece.