IPhone 3GS, the prototype includes a new front-facing camera (presumably for video calls), a larger lens and a flash for the usual camera at the rear of the phone, a micro-SIM instead of a standard SIM, a higher resolution display, and a secondary microphone for noise cancellation. The unit had a flat rear panel that was constructed of a clear material which was speculated to be either glass or plastic, and it featured a decorative aluminum strip that completely surrounded the edge of the phone. It had separate buttons for increasing and decreasing volume, instead of a single long button. Gizmodo also noted that the device's screen appeared to be slightly smaller than that of the iPhone 3GS, but apparently of higher resolution. They also found that its battery was about 15 percent larger than that of the iPhone 3GS and that the phone's internal components appeared to have been reduced in size from the iPhone 3GS to accommodate the larger battery.

Screen and input

The touchscreen is a 9 cm (3.5 in) liquid crystal display (320×480 px at 6.3 px/mm, 160 ppi,HVGA) with scratch-resistant glass, and 18-bit color (rendering 262,144 colors). The capacitive touchscreen is designed for a bare finger, or multiple fingers for multi-touch sensing. The touch and gesture features of the iPhone 3GS are based on technology originally developed byFingerWorks. Most gloves and styluses prevent the necessary electrical conductivity.The iPhone 3GSalso features a fingerprint-resistant oleophobic coating.

The display responds to three sensors. A proximity sensor deactivates the display and touchscreen when the device is brought near the face during a call. This is done to save battery power and to prevent inadvertent inputs from the user's face and ears. An ambient light sensor adjusts the display brightness which in turn saves battery power. A 3-axis accelerometer senses the orientation of the phone and changes the screen accordingly, allowing the user to easily switch between portrait and landscape mode.Photo browsing, web browsing, and music playing support both upright and left or right widescreen orientations.Unlike the iPad, the iPhone 3GS does not rotate the screen when turned upside-down, with the Home button above the screen. The 3.0 update added landscape support for still other applications, such as email, and introduced shaking the unit as a form of input.The accelerometer can also be used to control third party apps, notably games.

A software update in January 2008 allowed the first generation iPhone to use cell tower and Wi-Fi network locations trilateration,despite lacking GPS hardware. The iPhone 3G and iPhone 3GS employA-GPS, and the iPhone 3GS also has adigital compass.

The iPhone has three physical switches on the sides: wake/sleep, volume up and down, and ringer on and off. These are made of plastic on the original iPhone and metal on all later models. A single "Home" hardware button below the display brings up the main menu. The touchscreen furnishes the remainder of the user interface.

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