Question 19D1

A VHF-DSC (Digital Selective Calling) distress alert is initially transmitted on Channel 70. However, Channel 70 is exclusively designated for digital signaling (DSC messages) and is not used for voice communication. Once the digital distress alert has been sent and acknowledged (or detected), the international maritime protocol requires a switch to a voice channel for all subsequent communication. Channel 16 is the internationally recognized voice channel for distress, safety, and calling. All vessels and coast stations involved in a distress situation will switch to and monitor Channel 16 for follow-on voice transmissions to coordinate rescue efforts and provide detailed information. Therefore, while the alert is *sent* on Ch-70 (digitally), the *follow-on voice communication* occurs on Ch-16. Channels 12 and 13 are working voice channels, but not the designated international distress voice channel.