Mobile Phone Technology

2G - the change to digital.

Nokia 1011 - Nokia's first 2G phone.

image ©Nokia

The original mobile phone network was analogue, which had many problems. The security of phone calls was particularly problematic, as it was easy for people to listen in. In 1991, the network switched to digital, which is known as 2G. 2G allowed for greater network capacity, and, being digital, it enabled operators to enhance security. Initially, the only devices connected to the 2G network were mobile phones, and the emphasis was still on phone services.

As well as phone services, a basic SMS messaging service was introduced. SMS uses the spare capacity on the network control channel to send messages. Initially, SMS was used by network technicians for communication. SMS provided phone customers with a simple messaging system — something that had not been seen before.

Data was also supported, but initially only via a dial-up connection to the phone system, reflecting the way the internet was delivered to households at the time. Users could either have a phone call or send data, but not both at the same time. Speeds were measured in Kbps rather than Mbps. The internet was available, but it was very slow and used special technology (WAP rather than HTML). However, it was the internet on the phone.

Later, as data became more important, enhancements were made to 2G. The most notable of these was the introduction of GPRS, a separate packet-switched, always-on network for data. Later enhancements to this network included EDGE technology. By this time, 2G had become a respectable network, but it was still too slow for the modern user.

In the UK, there were four 2G networks: Vodafone, O2, Orange and T-Mobile. These operators, or their equivalents, still maintain a 2G network today. This provides a backup phone system in areas of difficult coverage where 4G calling is not available. 2G is also currently used for a number of Internet of Things (IoT) applications, most notably for smart meter communications, as well as for alarms, health sensors, weather recording, parking machines and traffic lights.

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