The use of DSC (Digital Selective Calling) on your VHF radio

If you attended a Boat Show recently and picked up one of those new VHF radios with the little distress button under a bright red protective door, then you should apply for your free MMSI (Maritime Mobile Service Identity) This unique number can then be permanently programmed into your new transceiver. Without this MMSI number, your new radio won't be able to use any of the new DSC features.

As many of you know, these new Digital Selective Calling radios will transmit an automated digital distress signal. The data sent out contains the MMSI and also your latitude & longitude if a GPS is wired to the radio. The MMSI is linked to your personal contact data and a full description of your vessel. This allows the Coast Guard, or any other similarly equipped vessel within VHF radio range, to determine your vessel's description (and relative position if a GPS is connected) without calling you back.

There's another bonus from having this MMSI serial number programmed into your radio. You and your boating friends can call one another silently and discreetly if you know their MMSI numbers. Just store your friend's number in your radio's calling menu, and then electronically page their radios without ever calling on VHF Ch-16. Your digital message will go out to them silently on the digital Ch-70. When the called vessel pushes the "respond" button on their own transceiver, both radios can automatically switch to an agreed voice channel, ready to begin a conversation.