IPhone 3GS and quad-band GSM/GPRS/EDGE radio, the 3GS also adds support for 7.2 Mbit/s HSDPA allowing faster downlink speeds though upload speeds remain the same as Apple had not implemented the HSUPA protocol. Other updates include the addition of a built-in Nike+iPod sensor which eliminates the need for an external sensor and allows native Nike+iPod support. The Bluetooth server on the iPhone 3GS has also been slightly improved adding support for Bluetooth 2.1 specifications. Voice Control was introduced as an exclusive feature of the iPhone 3GS and allows for the controlling of the phone and music features of the phone by voice.
IPhone 3GS There are two ways to activate Voice Control: hold the Home button while in the home screen for a few seconds; or, change the effect of what double-clicking the home button does so it will activate Voice Control (only on iOS 3.x; on iOS 4 or later, double clicking the Home button opens the multitasking bar). VoiceOver, Color Inversion, and Text Zoom were introduced as exclusive features to the iPhone 3GS. VoiceOver is a feature that dictates music details, system menus, text, and other things which was first introduced on the third generation iPod shuffle. Color inversion reverses the color