The Controls on the Sides and Front of Your iPhone
The front and sides of iPhones have a similar look across versions, although the iPhone 4 has added some new toys. On the front of your iPhone, regardless of the version you have, you find the following:
Ring/silent switch: This switch, which is on the left side of your iPhone, lets you quickly switch between ring mode and silent mode.
When the switch is set to ring mode — the up position, with no orange dot — your iPhone plays all sounds through the speaker on the bottom. When the switch is set to silent mode — the down position, with an orange dot visible on the switch — your iPhone doesn't make a sound when you receive a call or when an alert pops up on the screen.
Volume buttons: Two volume buttons are just below the ring/silent switch. The upper button increases the volume; the lower one decreases it. You use the volume buttons to raise or lower the loudness of the ringer, alerts, sound effects, songs, and movies. And during phone calls, the buttons adjust the voice loudness of the person you're speaking with, regardless of whether you're listening through the receiver, the speakerphone, or a headset.
Receiver: The receiver is the speaker that the iPhone uses for telephone calls. It naturally sits close to your ear whenever you hold your iPhone in the "talking on the phone" position.
Status bar: The status bar displays important information about your iPhone's functionality.
Touchscreen: You can use the iPhone's gorgeous high-resolution color touchscreen to navigate your iPhone.
Home button: No matter what you're doing, you can press the Home button at any time to display the Home screen.
App buttons: Each button on the Home screen launches an included iPhone app or one you've acquired from the App Store.
The Utilities button is the sole exception — it's a folder containing four app buttons: Clock, Calculator, Compass, and Voice Memos. The Utilities button appears only on iPhones with iOS 4 preinstalled. If you upgraded your iPhone to iOS 4, those four apps are where they were before the upgrade, not contained in a Utilities folder.
The iPhone 4 includes a couple of newly placed controls on the side and front, respectively:
SIM card tray: The SIM card tray is where you remove or replace the SIM card inside your iPhone. On the iPhone 4, the SIM card tray is on the right side.
Camera: The camera on the front of the iPhone 4 is tuned for FaceTime, so it has just the right field of view and focal length to focus on your face at arm's length, to present you in the best possible light.