IS-54 and
IS-136 are second-generation (
2G) mobile phone systems, known as
Digital AMPS (D-AMPS), and a further development of the north-american
1G mobile system
AMPS. It was once prevalent throughout the
Americas, particularly in the
United States and
Canada since the first commercial network was deployed in 1993. D-AMPS is considered
end-of-life, and existing networks have mostly been replaced by
GSM/
GPRS or
CDMA2000 technologies.