3G is a collection of third generation cellular data technologies. The first generation (1G) was introduced in 1982, while the second generation of cellular data technologies (2G) became standardized in the early 1990s. 3G technologies were introduced as early as 2001, but did not gain widespread use until 2007.
In order to be labeled "3G," a cellular data transfer standard must meet a set of specifications defined by the International Telecommunications Union, known as IMT-2000. For example, all 3G standards must provide a peak data transfer rate of at least 2 Mbps. Most 3G standards, however, provide much faster transfer rates of up to 14.4 Mbps.
While many cell phone companies market phones with "3G technology," there is no single 3G standard. Rather, different companies use their own technologies to achieve similar data transfer rates. For example, AT&T uses a 3G technology based on GSM, while Verizon uses a technology based on CDMA. Additionally, cell phone networks outside the United States use different IMT-2000 compliant standards to achieve 3G data transfer speeds.
3G precedes 4G, the fourth generation of cellular data technologies.