Internationally adopted DSC procedures are proscribed in Recommendation ITU-R M.541 Operational procedures for the use of digital selective calling equipment in the maritime mobile service, available for download at no cost. This DSC Procedures for Boaters have been simplified, adapted from ITU-R M.541. Operating procedures may vary somewhat among different radios, depending upon how the radio is designed. For complete information, consult the radios operating manual and ITU-R M.541.

HF marine radios may also include a DSC feature. In fact, USCG has discontinued HF voice distress watchkeeping in most locations and can only respond to HF distress calls from ships made using DSC. For more information see NAVCEN’s HF Distress and USCG Contact Frequencies page.