ed the 3G initiative, and it began in the late 1990s. In addition to uni- fying the world on one standard, the 3G initiative wanted to add high-speed data com- munications support to cellular networks. This would allow subscribers to check e-mail, browse the Web, log onto the corporate database, and generally be able to work all the time until commercial services are added, and we can work and play online, plugged in without wires wherever we are. 9.2.2.3 Additional data services (2.5G). It was reasonable to assume that it would take several years to define 3G standards and deploy 3G networks. As a result, the smaller goal of adding medium-speed services to existing 2G networks was defined. Stan- dards that enhance 2G networks by adding data services were sometimes called 2.5G. Each of the major 2G services had some enhancements. GSM was enhanced with General Packet Radio Service (GPRS) and Enhanced Data Rate for GSM Evolution (EDGE). GPRS adds data capacity to GSM via on-demand packet switching. Under op- timal conditions, rates are as high as 115 kbps are achieved by assigning the user ter- minal extra TDMA time slots for data when they are needed. EDGE is an enhancement of GPRS that has a theoretical maximum speed of 384 kbps. It achieves these higher rates through new algorithms that increase data per time slot. When U.S. TDMA became an ANSI interim standard (IS-136A and B), it already sup- ported data rates of up to 64 kbps and therefore could be classed as 2.5G. Its next evo- lution will be the addition of TDMA-EDGE (IS-136 Outdoor), which will be fast enough to be classified as 3G. cdmaOne standards evolved from the 2G IS-95 standard and include data rates of 64 kbps, possibly up to 115 kbps. However, before these data services have come into wide use, cdma20001xEV-DO has arrived, moving CDMA into 3G. 9.2.3 Third generation (3G) The 3G initiative had two goals: to add the capacity to carry user data at high speeds on cellular networks and to unify the world on a single standard. The ITU planned to 1However