DSC (Digital Selective Calling)
The digital radio alert built into modern marine radios — one button sends a distress alert with the vessel's identity and position.
Digital Selective Calling sends short digital messages on VHF channel 70 and on MF/HF frequencies. A distress alert carries the vessel's nine-digit MMSI and, if the radio is connected to a GPS, its position. Coast stations and ships in range receive it automatically.
When a rescue centre broadcasts "DSC DISTRESS ALERT RECEIVED", the alert typically could not be resolved: nobody answered on voice, or the position was missing. The MMSI in the text is sometimes the only clue to which vessel sent it.
What the archive shows
1,439 messages in this archive use “DSC (Digital Selective Calling)”, the earliest issued 1999-03-09 and the latest 2026-09-16. 7 of them are in force in the latest lists we collected. A hazard reported again and again counts once per message.
The largest yearly count is 2023, with 88 messages. Collection is incomplete between 2024-05 and 2026-08-17, so 2024, 2025 and 2026 are not comparable with fully collected years.
Nav aids accounts for 1,240 of 1,439 recorded messages (86%), the largest warning type group in this selection.
Located messages that use it fall in 27 sea areas; the most frequent are North Atlantic Ocean (198), Inner Seas off the West Coast of Scotland (193) and North Sea (174).
Messages that use it are issued most often in July (147 across all years) and least often in January (95).
By warning series: HYDROLANT 634, HYDROPAC 307, NAVAREA IV 292 and NAVAREA XII 136, and 3 more.
Messages using it, by year of issue
By month of issue, all years
Where it appears · 27 sea areas
In force now · 7
- HYDROPAC 2438/26 · Nav aids · South Pacific Ocean2026-08-26 · in force
EASTERN SOUTH PACIFIC. CHILE. MAGALLANES RADIO 53-09.92S 070-54.28W MF AND HF DSC RECEIVE SERVICES OFF AIR.
Magallanes radio 53-09.92S 070-54.28W mf and hf dsc receive services off air → - NAVAREA I 172/26 · Nav aids · North Sea2026-08-16 · in force
GMDSS. ENGLAND AND SCOTLAND EAST COAST. 1. MF R/T AND DSC SERVICES FROM CULLERCOATS SITE 55-04.4N 001-27.8W OFF AIR. 2. VHF DSC AND MF R/T AND DSC…
Mf r/t and dsc services from cullercoats site 55-04.4N 001-27.8W off air → - NAVAREA I 167/26 · Nav aids · Inner Seas off the West Coast of Scotland2026-08-08 · in force
GMDSS. SCOTLAND, WEST COAST. MF DSC SERVICE FROM TIREE SITE 56-30.2N 006-57.8W OFF AIR.
Mf dsc service from tiree site 56-30.2N 006-57.8W off air → - NAVAREA II 297/26 · Other2026-08-07 · in force
ACORES. RADIO SERVICES. HF SERVICE - MF SERVICE MF/HF DSC/VOICE ENTIRE AZORES ARCHIPELAGO IS NOT OPERATIONAL. A2 AREA COVERAGE IS NOT GUARANTEED.
Hf service - mf service mf/hf dsc/voice entire azores archipelago is not operational → - NAVAREA XII 486/26 · Other · North Atlantic Ocean2026-07-16 · in force
…BE TRANSMITTED FROM USCG REMOTE COMMUNICATION FACILITY GUAM 13-25.00N 144-50.00E. 3. DSC RESPONSES WILL BE TRANSMITTED FROM USCG REMOTE COMMUNICATION FACILITY POINT REYES…
Uscg remote communication facility honolulu 21-22.00N 158-09.00W transmit services unreliable → - NAVAREA IV 662/26 · Nav aids · Gulf of Mexico2026-07-07 · in force
…LOUISIANA. USCG REMOTE COMMUNICATION FACILITY NEW ORLEANS 29-53.00N 089-57.00W MF AND HF DSC OFF AIR.
Uscg remote communication facility new orleans 29-53.00N 089-57.00W mf and hf dsc off air →
How it reads in recent messages
- HYDROPAC 2673/26 · Nav aids · South Pacific Ocean2026-09-16
EASTERN SOUTH PACIFIC. CHILE. VALPARAISO RADIO 33-04.70S 071-36.80W DSC SERVICES OFF AIR.
Valparaiso radio 33-04.70S 071-36.80W dsc services off air → - HYDROPAC 2655/26 · Nav aids · South China Sea2026-09-14
NORTH PACIFIC. GUAM. 1. USCG REMOTE COMMUNICATION FACILITY GUAM 13-29.00N 114-50.00E DSC SERVICES INOPERATIVE AND BROADCAST SERVICES UNRELIABLE 161500Z TO 161730Z SEP. 2. CANCEL…
Uscg remote communication facility guam 13-29.00N 114-50.00E dsc services inoperative and broadcast services… → - NAVAREA XII 628/26 · Nav aids2026-09-14
NORTH PACIFIC. 1. DSC SERVICES INOPERATIVE AND BROADCAST SERVICES UNRELIABLE 161500Z TO 161730Z SEP AT USCG…
Dsc services inoperative and broadcast services unreliable 161500Z to 161730Z sep at uscg remote… → - NAVAREA IV 888/26 · Nav aids · North Atlantic Ocean2026-09-14
NORTH ATLANTIC. 1. DSC SERVICES INOPERATIVE AND BROADCAST SERVICES UNRELIABLE 161500Z TO 161730Z SEP AT USCG…
Dsc services inoperative and broadcast services unreliable 161500Z to 161730Z sep at uscg remote… → - NAVAREA XII 620/26 · Nav aids2026-09-10
NORTH PACIFIC. 1. HF DSC AND TRANSMIT UNRELIABLE 101400Z TO 110300Z SEP AT USCG REMOTE COMMUNICATION FACILITIES:…
Hf dsc and transmit unreliable 101400Z to 110300Z sep at uscg remote communication facilities: a. pt reyes… → - HYDROPAC 2609/26 · Nav aids · North Pacific Ocean2026-09-10
NORTH PACIFIC. GUAM. 1. USCG REMOTE COMMUNICATION FACILITY GUAM 13-29.00N 144-50.00E HF DSC AND TRANSMIT UNRELIABLE 101400Z TO 110300Z SEP. 2. CANCEL THIS MSG 110400Z SEP 26.
Uscg remote communication facility guam 13-29.00N 144-50.00E hf dsc and transmit unreliable 101400Z to… → - NAVAREA IV 869/26 · Nav aids · North Atlantic Ocean2026-09-10
NORTH ATLANTIC. 1. HF DSC AND TRANSMIT UNRELIABLE 101400Z TO 110300Z SEP AT USCG REMOTE COMMUNICATION FACILITIES:…
Hf dsc and transmit unreliable 101400Z to 110300Z sep at uscg remote communication facilities: a. boston… → - HYDROPAC 2599/26 · Nav aids · North Pacific Ocean2026-09-09
NORTH PACIFIC. GUAM. 1. USCG REMOTE COMMUNICATION FACILITY GUAM 13-29.00N 144-50.00E DSC AND HF UNRELIABLE 091530Z TO 100330Z SEP. 2. CANCEL THIS MSG 100430Z SEP 26.
Uscg remote communication facility guam 13-29.00N 144-50.00E dsc and hf unreliable 091530Z to 100330Z sep →
Earliest in the archive
- NAVAREA IV 62/99 · Other1999-03-09
BOSTON, MASSACHUSETTS (NMF) DSC SITE UNABLE TO RECEIVE UNTIL FURTHER NOTICE.
Boston, massachusetts (nmf) dsc site unable to receive until further notice →
Often in the same message
Related terms
- Distress signal received
- A rescue centre has received an alert — from a beacon, a radio call or a satellite terminal — and is asking ships to look.
- EPIRB
- Emergency Position-Indicating Radio Beacon: a distress beacon that sends a vessel's identity and position to rescue centres by satellite.
- GMDSS
- The Global Maritime Distress and Safety System: the internationally agreed set of radio services ships use for distress alerting and safety broadcasts.
- VHF / channel 16
- Very high frequency marine radio; channel 16 is the international distress, safety and calling channel.
Warning types that use it
- Incidents — Search-and-rescue broadcasts, published only once a case has been closed for 30 days: groundings, sinkings, capsizes, fires, man overboard, overdue vessels. Nothing here is live.
Counts cover the messages in this archive that use the term, recounted 2026-09-24; see coverage for what is collected and since when. Not for navigation — follow official NAVAREA and coastal broadcasts.