What is "2G" wireless technology? How does it relate to J2ME?

Bill Day

Cellular phone technologies have evolved in several major phases, denoted by "Generations", or "G" for short.

"2G" stands for second generation cellular technology. 2G systems use circuit-based, digital, voice centric technologies. 2G networks were deployed widely throughout the 1990s.

The three major competing 2G cellular technologies are Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), and Global System for Mobile (GSM). Of these, GSM has by far the largest number of users on a worldwide scale (600 million and growing as of fall 2001, approximately two thirds of all cellular users in the world today).

Since 2G networks are digital networks, they are capable of carrying data transmissions. Average data speed, though, is roughly equivalent to an early 1990s dial-up modem, around 9.6kpbs.

Because of 2G networks can support the transmission of data, they are able to support J2ME enabled phones. Several manufacturers are providing J2ME phones for 2G operators, though most are focusing the majority of the J2ME device efforts on 2.5G and 3G devices.

Many carriers and wireless operators are upgrading their 2G networks with 2.5G technology to increase the number of consumers they can service while also boosting data rates. For more on this, please refer to the related 2.5G FAQ entry. You may also want to read the 1G and 3G entries to learn about the history and future, respectively, of cellular technologies.