Apple also said the top surface of the touch-screen phone, which will sell for about $500 to $600 through a subscription with AT&T Inc. , has been upgraded from plastic to optical-quality glass, making it more resistant to scratches.
AT&T, the biggest U.S. wireless provider, has an exclusive agreement to sell the phone in the United States for at least two years. The company has said that more than a million people have inquired about the phone via e-mail.
The iPhone battery cannot be easily removed, unlike those of traditional cell phones, so power efficiency is an even more important feature in this device.
Sony Ericsson has touted a talk time of up to 9 hours for some of its Walkman music-playing phone models.
The Upstage music playing phone from Samsung has a battery life of up to 6.3 hours.
Apple said the iPhone can support up to eight hours of talk time, seven hours of video playback, or 24 hours of audio playback.
iPhone will be available in the US on June 29, 2007 in a 4GB model for $499 (US) and an 8GB model for $599 (US), and will work with either a PC or Mac.