Mobile phones were first developed in the 1940s as two-way radios for the military. Dr. Martin Cooper invented the first practical mobile phone in 1973. The first mobile phones available to the public were introduced in 1983 by Motorola and used analog technology. Throughout the 1990s, digital 2G technology improved mobile phones. Today, most phones use 3G digital technology, which allows data like emails and messages in addition to calls. Mobile phones connect to cellular networks provided by operators to make calls and access the internet. They have increasingly taken on additional functions like cameras, music players, and internet access.