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Marine Safety Alert: Ensuring proper configuration of digital selective calling (DSC)-equipped radios

March 2, 2023

The Coast Guard Office of Investigations and Analysis has released Marine Safety Alert 03-23 to remind marine radio users of the importance and value of properly configuring their Digital Selective Calling (DSC)-equipped Very High Frequency (VHF) radios to enable proper function during an emergency situation. When properly installed, DSC allows the mariner to simply hit the red DSC button in an emergency, resulting in the vessel’s geographic coordinates and registered Maritime Mobile Service Identities (MMSI) number to be transmitted to nearby DSC enabled vessels and shore-based VHF towers.

During a marine casualty involving the loss of life aboard a commercial fishing vessel, it was found that the DSC-equipped VHF radio was not properly configured with the vessel’s GPS system. While the Master was able to broadcast the vessel’s position before sinking, having the DSC alert properly enabled could have provided the master more opportunity to focus on emergency operations and egress from the sinking vessel, while still continuously broadcasting an emergency signal over VHF.

The Coast Guard strongly recommends that vessel owners, operators, and crewmembers with DSC-equipped VHF radios:

  • Obtain and properly register an MMSI number. Information to obtain/register a MMSI number can be found at

  • Ensure that your GPS and DSC-equipped radio are interconnected. Doing so may save your life in a distress situation! All DSC-equipped radios, and most GPS receivers, have an NMEA 0183 two-wire data protocol which allows for any model of GPS to be successfully interconnected to any model of radio, regardless of manufacturer. Before interconnecting your radio & GPS, consult the owner's manuals. Additional information on how to interconnect DPS-equipped radios with GPS receivers can be found at:

  • Confirm proper operation of your radio equipment. Testing procedures for your DSC-equipped radio can be reviewed in Marine Safety Information Bulletin (MSIB) 20-20 Change 1 which can be found at: Marine Safety Information Bulletins (

  • DSC functionality or operations questions may be submitted to the U.S. Coast Guard Navigation Center on its Contact Us webpage:

This Safety Alert is provided for informational purposes only and does not relieve any domestic or international safety, operational, or material requirements. The Safety Alert was developed by the Marine Board of Investigation for the Commercial Fishing Vessel SCANDIES ROSE sinking and distributed by the Office of Investigations and Analysis. Questions may be sent to

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This blog is not a replacement or substitute for the formal posting of regulations and updates or existing processes for receiving formal feedback of the same. Links provided on this blog will direct the reader to official publications, such as the Federal Register, Homeport and the Code of Federal Regulations. These publications remain the official source for regulatory information published by the Coast Guard.