Routine calling – with DSC

DSC does not change how we talk on the radio but hopeful makes arranging the conversation easier.

To call someone using DSC you need to know their MMSI number.

If you know a boat’s MMSI number you can initiate a DSC Routine Announcement which sends a digital message to that vessel inviting them to talk.

The advantage is that you do not need to know which channel they are currently on, as the announcements will get through regardless.

On the Icom radios is is done as follows:

– Press “Menu”
– Select “Individual Call”
– Press “Enter”

If their MMSI is in your “phone book”


If their MMSI is not in you “phone book”

 – Scroll using the ARROWS to the name of the vessel you wish to call.    – Scroll using the ARROWS to Manual Input
– Press “Enter”
 – Press”Enter”    – Enter the MMSI number using the ARROWS to select the number and CH button to move to the right and 16 button to move to the left.
     – Press”Enter”

– Scroll using the ARROWS to the working channel you wish to call the vessel on.
– Press “Enter”
– Press “Enter” again to confirm
– the Announcement has been sent.

An alarm then goes off on the other radio (if it is on and in range).

Wait for an acknowledgement. At this point your radio and their radio will change automatically to the working channel. Then start your voice call on the working channel – YOU talk first!

From this point on, the voice communication is undertaken in the same way as without DSC. See the Calling without DSC page for more details.

If this does not make it clear, see the video below:

Calling the Coastguard

Calling the coastguard on DSC is a little different, don’t fall into the trap of not knowing how. See the guide below.

PDF Calling the Coastguard

For a list of Coastguard MMSI Numbers see the MMSI page

What if I don’t have their MMSI number?
If you don’t know a vessel’s MMSI number you cannot use DSC calling. You should call the vessel on channel 16 and then move to a working channel to pass your message. See the page on non-DSC calling.

What is ATIS?

ATIS is “Automatic Identity Signal” which is an similar to DSC in that it sends a digital signal that identifies your vessels however it is different in that:
– it transmits you ATIS number digitally automatically every time you release the transmit button
– the digital transmitting is send on the same channel as the voice transmission.

It is illegal to use ATIS in UK waters but required for all transmissions made within the inland waterways of mainland Europe (note: not the inland waterways of the UK). Some modern radios can be switched between DSC and ATIS, either by the owner or by an agent.

To use ATIS you need a unique ATIS number, for UK liecenced vessels this is made up from the MMSI number prefixed with the number 9.

DSC and/or 25W transmisions are illegal in the inland waterways of mainland Europe.

For more information on ATIS and license see the OfCom website [OfCom: ATIS…]


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