2G

Lore & Background

In 1990, AT&T Bell Labs engineers Jesse Russell, Farhad Barzegar and Can A. Eryaman filed a patent for a digital mobile phone supporting digital data transmission. Their patent was cited years later by Nokia and Motorola when developing 2G digital mobile phones. 2G was first commercially launched in 1991 by Radiolinja (now part of Elisa Oyj) in Finland in the form of GSM, defined by the European Telecommunications Standards Institute (ETSI). The Telecommunications Industry Association (TIA) defined the cdmaOne (IS-95) 2G standard, with an eight to tenfold increase in voice call capacity compared to analog AMPS; its first deployment was in 1995. In North America, Digital AMPS (IS-54 and IS-136) and cdmaOne were dominant, but GSM was also used.

Later 2G releases in the GSM space, often called 2.5G and 2.75G, include General Packet Radio Service (GPRS) and Enhanced Data Rates for GSM Evolution (EDGE). GPRS enables packet-based data transmission by dynamically allocating multiple timeslots, achieving a theoretical maximum of 40 kbit/s. EDGE, introduced with 8PSK encoding, increased the theoretical maximum to 384 kbit/s. Evolved EDGE (2.875G) further improved throughput and reduced latencies to 80 ms using dual carrier support, dual antennas, and turbo codes, reaching peak data rates up to 1 Mbit/s, but was never widely deployed; as of 2016, no commercial networks supported it.

Reader's Guide

2G networks were primarily designed to support voice calls and Short Message Service (SMS), with later advancements such as GPRS enabling always-on packet data services including email and limited internet access. Three primary benefits over 1G were digitally encrypted phone conversations (at least between mobile phone and base station), significantly more efficient use of radio frequency spectrum, and data services starting with SMS then expanding to MMS. The transition to digital technology enabled encryption for voice calls and data transmission, improving security while increasing capacity and efficiency.

2G has been superseded by newer technologies (3G, 4G, 5G), but as of 2023 remained available in most parts of the world, excluding the majority of carriers in North America, East Asia, and Australia. Many modern LTE devices could fall back to 2G for calls, especially in rural areas. In some places, 3G was shut down before 2G—Vodafone switched off 3G across Europe in 2020 while retaining 2G as a fallback. T-Mobile in the US shut down 3G in 2022 but kept 2G GSM until August 3, 2026. Various carriers in the US, Japan, Australia, and other countries have announced or completed 2G shutdowns to reuse frequencies for newer technologies. As a legacy protocol, 2G connectivity is considered insecure; well-known methods to attack GSM weaknesses have existed since 2009, with practical use in crime. Android 12 and later provide a setting to disable 2G; iOS 16 and later can disable it via Lockdown Mode. In some parts of the world, including the UK, 2G remains widely used for older feature phones and IoT devices such as smart meters and vehicle trackers to avoid high patent licensing costs of newer technologies.

Did You Know?

• The cdmaOne standard provided an eight to tenfold increase in voice call capacity over analog AMPS.
• Android 12 and later include a network setting to disable 2G connectivity on a device.

The Digital Leap

The defining breakthrough of 2G was the replacement of analog radio signals with digital ones in the communication link between mobile handsets and base stations. This seemingly technical shift unlocked a cascade of capabilities that 1G networks simply could not offer. For the first time, voice calls and data transmissions could be encrypted, at least over the air interface between the phone and the tower, giving mobile communications a meaningful layer of security. The digital approach also made far more efficient use of the radio frequency spectrum, allowing carriers to serve more subscribers within the same bandwidth. Beyond voice, 2G introduced Short Message Service, and later Multimedia Messaging Service, laying the groundwork for mobile data. The intellectual seeds of this transition trace back to 1990, when AT&T Bell Labs engineers Jesse Russell, Farhad Barzegar, and Can A. Eryaman filed a patent for a digital mobile phone capable of transmitting digital data—a patent later cited by Nokia and Motorola during their own 2G development efforts.

A World of Standards

Rather than a single universal standard, 2G emerged as a patchwork of competing technologies, each shaped by regional regulatory bodies and carrier preferences. The GSM standard, defined by the European Telecommunications Standards Institute, ultimately became the most widely adopted framework in mobile history. Its first commercial deployment came in 1991, when Finland's Radiolinja—now part of Elisa Oyj—switched on the service. In North America, the Telecommunications Industry Association championed a different path: cdmaOne, designated IS-95, which delivered an eight- to tenfold increase in voice call capacity over the older analog AMPS system. cdmaOne's first deployment followed in 1995, and alongside Digital AMPS (IS-54 and IS-136), it dominated the continent while GSM also found a foothold. Japan carved out its own niche with the Personal Digital Cellular and Personal Handy-phone System standards. This fragmentation meant that 2G was never a single technology but a family of digital systems, each with its own architecture, yet all sharing the fundamental leap from analog to digital signaling.

The 2.5G and 2.75G Bridge

Between the original 2G voice-and-SMS era and the broadband promise of 3G, operators squeezed incremental data speeds out of existing GSM infrastructure through what became known as 2.5G and 2.75G. General Packet Radio Service introduced a packet-switched domain running alongside the traditional circuit-switched one, dynamically allocating multiple timeslots to active users. The theoretical ceiling was modest—40 kilobits per second—but it was enough to support email and rudimentary web browsing. EDGE pushed further by adopting 8PSK modulation, letting each symbol at the unchanged 270.833 samples-per-second rate carry three bits instead of one and tripling the theoretical maximum to 384 kilobits per second. AT&T brought EDGE to market in 2003. A final iteration, Evolved EDGE, combined improved modulation, dual-carrier support, dual antennas, and turbo codes to reach one megabit per second with latencies as low as 80 milliseconds. Yet by the time it was ready, most operators had already pivoted to UMTS and LTE, and as of 2016 no commercial network had deployed it.

The Long Goodbye

Though 2G has been technically superseded by 3G, 4G, and 5G, its retirement has proven far more gradual than the arrival of each successor. As of 2023, GSM and cdmaOne networks remained operational across most of the globe, with the notable exceptions being the majority of carriers in North America, East Asia, and Australia. One reason for 2G's stubborn persistence is its role as a fallback: many LTE-capable handsets still drop back to 2G for voice calls, a lifeline in rural regions where 3G or 4G coverage is absent. The irony is that in some markets 3G is being retired before 2G. Vodafone, for instance, switched off its European 3G network in 2020 yet kept 2G running as a safety net. In the United States, T-Mobile ended its 3G service in 2022 but scheduled the final decommissioning of its 2G GSM network for August 3, 2026. Carriers in the U.S., Japan, and Australia have all signaled 2G shutdowns, but the technology that first put digital mobile communication in people's pockets continues to hold on, one region at a time.