A.3. Improved Digital Cellular (2.5G)

In the late 1990s, operators could see that demand for voice phones was saturating. They could foresee the day when everybody who wanted a mobile phone would have one. At the same time, the Internet was becoming ubiquitous, and users were starting to demand better data access from their mobile phones. Operators looked for ways to expand the data capacity of their mobile networks while taking advantage of their existing infrastructure investments. GSM operators expanded their GSM/GPRS networks to a new standard called Enhanced Data for GSM Evolution (EDGE), which further improved available data rates and made efficient use of GSM equipment the operators already had installed. CDMA operators capitalized on similar improvements in that domain, with standards such as CDMA2000 1X. The theoretical data rates were now in the hundreds of kilobits per second, though the actual data rates were still much lower. Phones running Android can be expected to have at least 2.5G data connectivity.

A second wave of data access improvement (sometimes referred to as 2.75G) further improved data rates, implemented by High Speed Packet Access (HSPA) for GSM and EV-DO (EVolution Data Optimized, or sometimes translated as EVolution Data Only) for CDMA. Theoretical data rates were now in the multimegabit-per-second range, and most Android phones can be expected to have these technologies, if not 3G.