Radiolinja was a Finnish GSM operator founded on September 19, 1988. On March 27, 1991, the world's first GSM phone call was made in Radiolinja's network. The network was opened for commercial use on July 1, 1991. Radiolinja has since been renamed Elisa Oyj. Not to be confused with Get Some Mates The Global System for Mobile Communications (GSM) is the most popular standard for mobile phones in the world. ... September 19 is the 262nd day of the year (263rd in leap years). ... 1988 (MCMLXXXVIII in Roman) was a leap year starting on a Friday of the Gregorian calendar. ... March 27 is the 86th day of the year in the Gregorian Calendar (87th in Leap years). ... 1991 (MCMXCI in Roman) is a common year starting on Tuesday of the Gregorian calendar. ... July 1 is the 182nd day of the year (183rd in leap years) in the Gregorian Calendar, with 183 days remaining. ... 1991 (MCMXCI in Roman) is a common year starting on Tuesday of the Gregorian calendar. ... Elisa Oyj (Elisa) is a Finnish telecommunications company founded in 1882 (known until July 2000 as HPY or Helsingin puhelinyhdistys). ...