The iPhone 4 and iPhone 5 are sleek devices with a few buttons, windows, and connectors on the top, sides, and bottom of the device. Here’s a brief look at what each of them does.

The top and side of your iPhone

On the top of your iPhone, you’ll find a microphone and the sleep/wake button, as shown in the following figure. The SIM card tray is on one side, and the ring/silent switch and volume buttons are on the other side.

• Microphone: Used for FaceTime calls and noise suppression during phone calls.
• SIM card tray: The SIM card tray is where you remove or replace the SIM card inside your iPhone.A SIM (Subscriber Identity Module) card is a removable smart card used to identify mobile phones. It allows users to change phones by moving the SIM card from one phone to another. Kind of — the iPhone 4 and 4s use a micro-SIM, while all iPhone 5 models use a smaller version called a nano-SIM. And, of course, they’re not compatible.
• Sleep/wake button: This button is used to lock or unlock your iPhone and to turn your iPhone on or off. When your iPhone is locked, you can still receive calls and text messages, but nothing happens if you touch its screen. When your iPhone is turned off, all incoming calls go directly to voicemail.
• Headset jack (iPhone 4 and 4s only): The headset jack on the iPhone 4 and 4s lets you plug in the included iPhone headset, which looks a lot like white iPod earbuds. Unlike iPod earbuds, however, the iPhone headset has a microphone so that you can talk as well as listen.
• 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.Silent mode is overridden, however, by alarms you set in the built-in Clock app, iPod audio, and selecting sounds such as ringtones and alert sounds in the Settings app.If your phone is set to ring mode and you want to silence it quickly, press the sleep/wake button on the top of the iPhone or press one of the volume buttons.
• 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.

The bottom of your iPhone

On the bottom of your iPhone, you’ll find the microphone, the dock connector or Lightning connector, the speaker, and the headset jack (on the iPhone 5), as shown in the following figure.

• Headset jack (iPhone 5, 5c, and 5s): The headset jack lets you plug in the included iPhone headset, which looks a lot like EarPods but with an elliptical shape.

• Microphone: The microphone lets callers hear your voice when you’re not using a headset.The iPhone 4 and 4s have two microphones (top and bottom); iPhone 5 models sport three (top front, top back, and bottom). The top ones are used for FaceTime calls and also work with the main mic (located on the bottom) to suppress unwanted and distracting background sounds on phone calls using dual-mic noise suppression or beam-forming technology.

• Dock or Lightning connector: The Lightning connector (dock connector on the iPhone 4 and 4s) has three purposes. One, you can use it to recharge your iPhone’s battery. Simply connect one end of the included Lightning or dock connector to a USB cable to the iPhone and the other end to the USB power adapter. Two, you can use the port to synchronize. Connect one end of the cable to the port on your iPhone and the other end to a USB port on your Mac or PC. And three, you can use the Lightning or dock connector port to connect your iPhone to other devices, such as a camera or television using an adapter such as the Camera Connection Kit or one of Apple’s A/V adapter cables.

• Speaker: The speaker is used by the iPhone’s built-in speakerphone and plays audio — music or video soundtracks — if no headset is plugged in. It also plays the ringtone you hear when you receive a call.

The front of your iPhone

On the front of your iPhone, you’ll find the following:

• Camera: The camera on the front of the iPhone 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, which presents you in the best possible light.
  

• 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.

• Touchscreen: The iPhone’s high-resolution color touchscreen is gorgeous. Try not to drool all over it.

• Home button (and Touch ID sensor on the iPhone 5s): No matter what you’re doing, you can press the Home button at any time to display the Home screen, which is the screen shown in the next figure.

• App buttons: Each button on the (first) Home screen launches an included iPhone app or one you’ve acquired from the App Store. Note that the Newsstand button is a folder.

The back of your iPhone

On the back of your iPhone is a camera lens. It’s the little circle in the top-left corner. The iPhone also has a little LED (or a pair of little LEDs on the iPhone 5s) next to the camera lens for use as a flash for still photos, as a floodlight for videos, and as a flashlight (turn it on and off in Control Center).

Finally, iPhone 5 models have a third microphone on the back (refer to the first figure).