Apple iPhone 3G

Design
The iPhone 3G's edges are slightly tapered to accommodate the curved back, making the device thinner around its perimeter than its predecessor. Its dimension is 115.5 x 62.1 x 12.3 mm and weight 133 grams. It is available with 8 GB or 16 GB. At 3.5 inches and 480x320 pixels at 163 dots per inch and still produces brilliant colors, sharp graphics, and fluid movements. The layout of the home screen is identical to that on the first version, though it brings two new icons from the outset: A Contacts and the App Store icon to open the iTunes App Store. The display's glass surface, accelerometer feature, touch interface, and secondary menus remain the same.
The iPhone's 3G controls reveal a few changes, but none will surprise a current iPhone user. The Home button sits below the display, while the volume rocker and ringer mute switch rest on the left spine. The Power/sleep button rests on top of the phone in its normal position. All controls are now silver instead of black. The SIM card slot has not moved either, and Apple now includes a SIM removal tool in the box. At the bottom, there are the speaker, the microphone, and the charger port. iPhone 3G uses 3.5mm standard headset jack so we can use any 3.5mm headset.

Operating System
iPhone 3G uses iOS 2.0 from Apple when it was first released, but you can update to iOS 4.2.1. It is a variant of the same core that is found in Mac OS X v10.4.10. It powered by 620 MHz (underclocked at 412 MHz) Samsung 32-bit RISC ARM 1176JZ(F)-S v1.0 processor and PowerVR MBX Lite 3D GPU.
The home screen can be accessed at any time by a hardware button below the screen, closing the open application in the process. By default, the Home screen contains the following icons: Messages (SMS and MMS messaging), Calendar, Photos, Camera, YouTube, Stocks, Maps (Google Maps), Weather, Voice Memos, Notes, Clock, Calculator, Settings, iTunes (store), and App Store. Docked at the base of the screen, four icons for Phone, Mail, Safari (browser), and iPod (multimedia player) delineate the iPhone's main purposes.

Multimedia
iPhone 3G uses a 2 megapixel camera with geo-tagging but without video recording. The quality to play music is always as good as other Apple’s product. Music and video quality were largely unchanged. It continues to deliver an excellent music and video experience.

Internet and Connectivity
iPhone 3G uses a quad-band (850/900/1800/1900MHz) GSM and support 3g networks. It also equipped with A-GPS, Wi-Fi 802.11 b/g for internet connectivity in the hotspot area, and Bluetooth to connect with other devices.
Safari is the iPhone's default web browser. It displays pages similar to its Mac and Windows counterparts. Web pages may be viewed in portrait or landscape mode. It supports automatic zooming by pinching together or spreading apart fingertips on the screen, or by double-tapping text or images.