Wi-Fi Standards and Speeds

• The first-generation iPhone, the second generation iPhone 3G and the third-generation iPhone 3GS are equipped with only the 802.11b and 802.11g Wi-Fi standards. The 802.11b standard produces data transfer speeds of up to 11 megabits per second, while the 802.11g standard transfers data at up to 54Mbps. In addition to these standards, the iPhone 4 also comes with the 802.11n standard, which transfers data at up to 140Mbps. The fourth Wi-Fi standard, 802.11a, isn't included on any of the iPhones but is capable of the same speeds as the 802.11g standard. By default, the iPhones use the fastest available standard for transferring data via Wi-Fi, while the other standards act as backups for when the faster standard is unavailable or the content being transferred is incompatible.
  
  

Wi-Fi Vs. 2G Network

• Each of the iPhone versions connect to the 2G and 3G wireless networks, except the first-generation iPhone, which is capable of accessing only the 2G network. The 2G network's General Packet Radio Service transfers data on the iPhones at between 32 and 48 kilobits per second. Enhanced Data for Global Evolution, or EDGE, technology is a direct product of the GPRS protocol and produces speeds of up to 236Kbps.
  
  

Wi-Fi Vs. 3G Network

• Each generation of the iPhone, except the first-generation model, accesses the 3G network using Evolution Data-Optimized and High-Speed Downlink Packet Access technologies. The EVDO protocol produces transfer rates of up to 2.3Mbps, while the HSDPA protocol transfers data at up to 7.2Mbps on the iPhones. Because 2G and 3G network transfer speeds are considerably slower than those provided by Wi-Fi connections, many iPhone users opt to connect to the Internet using the phone's Wi-Fi capability instead.
  
  

Miscellaneous

• Wi-Fi is a trademarked name of the Wi-Fi Alliance and isn't an abbreviation or acronym. WiMAX technology, which is based on the IEEE 802.16 standard, is the next step in Wi-Fi technology and increases the connectivity range from 100 to 300 feet, as offered by Wi-Fi, to up to 30 miles. Currently, WiMAX is included on only a handful of mobile phones and, as of July 2011, isn't offered on any of the iPhone models.