As previously mentioned, the first commercial cellular systems were launched in the Nordic countries of Sweden, Denmark, Finland and Norway in 1981. The analog technology used for these systems was NMT – the Nordic Mobile Telephone standard – which was developed jointly between the operators in the four Nordic countries. In the U.S.A, commercial cellular was launched in October 1983 in Chicago, and the analog technology was called AMPS (Advanced Mobile Phone Service). Since then a host of other access methods has been introduced ranging from Total Access Communications System (TACS), a standard deployed initially in the UK in 1985 derived from AMPS to digital technologies.