query: When was the first cellphone developed?
passage: History of mobile phones
Prior to 1973, mobile telephony was limited to phones installed in cars and other vehicles.[19] Motorola was the first company to produce a handheld mobile phone. On April 3, 1973, Martin Cooper, a Motorola researcher and executive, made the first mobile telephone call from handheld subscriber equipment, placing a call to Dr. Joel S. Engel of Bell Labs, his rival.[25][26][27] The prototype handheld phone used by Dr. Cooper weighed 1.1 kilograms (2.4lb) and measured 23 by 13 by 4.5 centimetres (9.1 by 5.1 by 1.8in). The prototype offered a talk time of just 30 minutes and took 10 hours to re-charge.[28]
passage: Mobile phone operator
The first commercially automated cellular network (the 1G generation) was launched in Japan by NTT in 1979. The initial launch network covered the full metropolitan area of Tokyo's over 20 million inhabitants with a cellular network of 23 base stations. Within five years, the NTT network had been expanded to cover the whole population of Japan and became the first nationwide 1G network. Several other countries also launched 1G networks in the early 1980s including the UK, Mexico and Canada.