The Mandate by CEPT and the First Action Plan of 1982 The mandate given to the Technical Committee GSM by CEPT in mid-1982 requested the ‘‘harmonisation of a public mobile communication system in the 900 MHz band’’. 2 This decision took place during the very hot promotion phase for ISDN. Therefore it is remarkable to note that GSM was not defined as a ‘‘mobile ISDN’’. Instead the decision leaves the nature of the GSM open, but requests the study of the interconnection with ISDN. ...