Audio Playback
Testing conducted by Apple in May 2009 using preproduction iPhone 3GS units and software. The playlist consisted of 358 unique audio tracks, a combination of content imported from CDs using iTunes (128-Kbps AAC encoding) and content purchased from the iTunes Store (256-Kbps AAC encoding). All settings were default except: Call Forwarding was turned on; Wi-Fi was associated with a network; the Wi-Fi feature Ask to Join Networks and Auto-Brightness were turned off. Battery life depends on the cellular network, location, signal strength, feature configuration, usage, and many other factors. Battery tests are conducted using specific iPhone units; actual results may vary.