In June 1999 the IEC's Committee of Action (CA) decided to take a new structure for the fieldbus standards beginning with a first edition valid at the January 1, 2000, in time for the new millennium: There is a large IEC 61158 standard, where all fieldbuses find their place. The experts have decided that the structure of IEC 61158 is maintained according to different layers, divided into services and protocols. The individual fieldbuses are incorporated into this structure as different types.