RTCM SC101

RTCM Recommended Minimum Standard for DSC, Version 1.0, 10 Aug 1995, RTCM Paper 56-95/SC101-STD. Applies to VHF and to MF/HF. This standard is not generally recognized outside of the U.S. and should be replaced soon by the ITU Class D and E SC101 required capabilities include:

• Distress call
• All-ships call
• Individual station call
• Use of distress and routine priorities
• Use of safety priority (MF/HF only)
• Distress coordinates
• Time for last (distress) position update
• Acknowledgment or unable to comply response
• Receive distress relay and distress acknowledgment calls
• Receive Geographical area calls
• Test call (MF/HF only)
• Alarm

ITU-R Rec. M.825-3:

DSC transponder system for Vessel Traffic Services or ship- to-ship interrogation and identification. Rec. M.825 is superseded by the Universal Shipborne Automatic Identification System.

ITU-R Rec. M.821:

Optional expansion to DSC protocol Perhaps the most important M.821 expansion, now incorporated in most new DSC-equipped radios, improves the accuracy of distress position from 1 mile to the accuracy of your interconnected GPS receiver (about 13 meters).

• USCG Notice to Mariners MF/HF DSC Guidelines (pdf)
• DSC Operational Procedures for Ships
• How Digital Selective Calling Works
• Maritime Mobile Service Identities Explained
• Why Coast Guard Supports DSC on Marine Radios