Module 8 - Digital Selective Calling
False DSC Distress Alert
ITU Resolution 349 (Rev.WRC-23) gives the VHF DSC cancellation sequence. Reset the equipment immediately. If the set supports cancellation, cancel the alert using the equipment procedure. Then set Channel 16 and transmit an All Stations broadcast giving vessel name, call sign and MMSI and cancelling the false distress alert.
Do not transmit another distress alert, switch the radio off and hope, or omit the identity through embarrassment. Receiving stations need to connect the voice cancellation to the digital alert they saw. Continue listening and comply with rescue-coordination or coast-station instructions; record and report the incident as required by the operator's procedures.
Prevention still matters: keep the protected control guarded, brief crew, confirm position and nature of distress before a composed alert, and use approved training or test facilities. But once an alert has gone, recovery takes priority over blame.
| Order | Action | Purpose |
|---|---|---|
| 1 | Reset the equipment immediately | Stop repeat alert behaviour |
| 2 | Use set cancellation if available | Cancel digitally where supported |
| 3 | Set Channel 16 | Reach vessels and coast stations by voice |
| 4 | Broadcast All Stations with name, call sign, MMSI and cancellation | Tie the correction to the false alert |
Optional quick check
Section 6 of 9
Which action completes the VHF DSC false-alert recovery after reset and any set cancellation?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
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