Circulars are addressed to all the participants in the work of the ITU Telecommunication Development Sector and contain information of general interest such as the meeting schedule, work procedures, the list of hotels, etc.
Study groups diffuse Circulars in order to implement the provisions of WTDC regarding the approval and deletion of recommendations or to distribute questionnaires.
The numbering of circulars continues through the cycle between two World Telecommunication Development Conferences. The current cycle is from 1 January 2011 to 31 December 2014.
General Circular Letters (CLs)
Study Group Circular Letters (CLs)
Multiple Destination Letters (DMs)