2G

2G, or second-generation cellular network technology, marks the transition from analog to digital communication in mobile networks. Defined by the European Telecommunications Standards Institute (ETSI) under the GSM standard, which became the first globally adopted framework for mobile communications, 2G was first commercially launched in 1991 by Radiolinja (now part of Elisa Oyj) in Finland.^[1] Following its introduction, the earlier mobile wireless network systems were retroactively designated as 1G. 2G networks were primarily designed to support voice calls and Short Message Service (SMS), with later advancements such as General Packet Radio Service (GPRS) enabling basic data services, including email and limited internet access. Unlike 1G networks, which used analog radio signals, 2G networks utilized digital radio signals for communication between mobile devices and base stations. This transition to digital technology enabled the implementation of encryption for voice calls and data transmission, significantly improving the security of mobile communications while also increasing capacity and efficiency compared to earlier analog systems. 2G was succeeded by 3G technology, which provided higher data transfer rates and expanded mobile internet capabilities.

The most common 2G technology was the time-division multiple access (TDMA)-based GSM standard, used in most of the world outside Japan.^{[citation needed]} In North America, Digital AMPS (IS-54 and IS-136) and cdmaOne (IS-95) were dominant, but GSM was also used.^{[2][citation needed]} In Japan the ubiquitous system was Personal Digital Cellular (PDC), though another, Personal Handy-phone System (PHS), also existed.^{[citation needed]}

Three primary benefits of 2G networks over their 1G predecessors were:

1. Digitally encrypted phone conversations, at least between the mobile phone and the cellular base station but not necessarily in the rest of the network.
2. Significantly more efficient use of the radio frequency spectrum enabling more users per frequency band.
3. Data services for mobile, starting with SMS text messages then expanding to Multimedia Messaging Service (MMS).

With General Packet Radio Service (GPRS), 2G offers a theoretical maximum transfer speed of 40 kbit/s (5 kB/s).^[3] With EDGE (Enhanced Data Rates for GSM Evolution), there is a theoretical maximum transfer speed of 384 kbit/s (48 kB/s).^[3]