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New MMSI numbering scheme for handheld VHF with DSC and GPS

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he International Telecommunications Union (ITU) has decided to recommend a new scheme for MMSI numbers on handheld VHF sets with DSC and GPS, Recommendation ITU-R M.585-5 on the Assignment and use of 9-digit numerical identities in the maritime mobile service.

In Norway the recombination has been implemented from January 1. 2013 and will be implemented like this.

The structure of standatd MMSI's are like this MIDXXXXXX, MID denotes the administration having jurisdiction over the ship station and XXXXXX is a unique number for the vessel.

The new format for handheld VHF with DCS and GPS is 8MIDXXXXX.
The number 8 identifies the unit as a handheld, XXXXX. is one digit less than the "normal"

Handheld VHF's belonging to a boat with fixed VHF can use the existing MMSI with 8 added at the start and the last digit (0) removed (it seems that the Norwegian authorities has been planning for this - it was Norway who proposed this change).

It is also possible to the get new MMSI's with the leading 8 for handheld sets when the set is not associated with a fixed station)

The reasons for this change are.
-DSC calling can be used for communication between handheld and the boats fixed VHF
-It will be possible for the rescue services to know that a DSC alarm is from a handheld set with its limitations..

15 Replies

  • Re "DSC calling can be used for communication between handheld and the boats fixed VHF":
    This is indeed a very important function that most people owning a fixed VHF and buying a handheld VHF will expect without thinking about it. But technically it is not quite as obvious. As no one would want to have their radios ring on a incoming call when they send out a call request (routine, safety or distress), a simple solution for a radio's software would be to ignore any incoming calls with it's own MMSI. If that approach were taken by the manufacturers, then it is exactly this function that wouldn't work.
    In my own experience, I have been able to call a Simrad RS82 from a SH HX851 handheld and vice versa and the combination SH HX851 and SH GX2000 also works when all these radios are set to the same MMSI.
    So it seems that the software writers have been smarter about this (i.e., ignore incoming calls with same MMSI only at the very moment an outgoing call is sent?) and the change in numbering scheme is not absolutely required for this function.
    In Germany I have been officially assigned the same MMSI for my fixed radio and handheld two years ago.
    We will see if it will be officially revoked and whether I will be forced to send in my handheld to have the MMSI erased.
    The idea is good but they should have thought of this before. And its not like no one could possibly have thought of the above problem before.

  • Here in Norway the new scheme will be effective from January 1th 2013. Existing sets will not need to be reprogrammed.

  • Didn't then end in 0, so that the MMSI owner could setup their own groups starting from 1?

  • Dan,

    Only a few MMSI assigning offices have given out MMSI numbers that all end in 0.

    Kees / MMSI 244060807

  • Can someone tell me whom I should contact to be assigned an MMSI number
    for my yacht. I am in the process of registering my boat with the
    Norwegian Ordinar Ship registry.

    I need this to use AIS, apparently.

  • After registering the boat in "Norwegian Ordinary Ship registry" you get assigned a call sign.

    Then you go to and apply for a license, with the license you get the MMSI number.

    For pleasure crafts the cost is NOK 475 a year.

  • I've had the same successful experience as Henning with various DSC radios using the same MMSI. So I'm not sure that's a 'problem' that needs fixing. However I like this new scheme as it identifies DSC handhelds and also creates more MMSI numbers. Plus, though not mentioned, hopefully DSC handhelds are registered to person, not a boat, like a PLB. Hopefully, too, there will a place in the registration where we can reference the boat the handheld will most likely be used.

  • As Henning wrote it should not be difficult to program a radio to ignore it's own MMSI.
    But it would be more of a challenge with three sets using the same MMSI?

    So having the possibility to get more than one MMSI assigned could be good for some users.

  • Update: 2016 US usage.

    in conversations with USCG, US FCC, and various tech supports.

    1. ITU M-585-7
    Annex 1 Section 5 has discussion on "Assignment of identification to craft associated with a parent ship"
    Per that section:
    1 Craft associated with a parent ship, need unique identification (their format is a 98MIDxxxx were the 98 indicates subordinate vessel) The MID represents the administration having jurisdiction over the call identity for the craft associated with a parent ship.
    2 This numbering format is only valid for devices on board craft associated with a parent
    ship. A craft may carry multiple devices which would be identified by the MMSI assigned to the
    craft. These devices may be located in lifeboats, life-rafts, rescue-boats or other craft belonging to a
    parent ship.
    3 A unique MMSI should be assigned for each craft associated with a parent ship and will
    have to be separately registered and linked to the MMSI of the parent ship.
    4 The format scheme shown above will accommodate 10 000 crafts associated with parent
    ships per MID. If the administration concerned has more than 10 000 they may use an additional
    country code (MID) if it is already assigned by the ITU giving a further 10 000 identities.
    5 The assigned MMSI to these craft associated with a parent ship should also be available
    from the ITU MARS database

    The problem in the US is that the FCC and it's delegates by MOU such as Boat US don't have blocks of numbers that start with 98, and the USCG HQ staff indicated doubt that most field staff would understand that the 98 was a type designation vs a foreign.

    If you plan to use a handheld with DSC, there's the ITU 585-7 Annex 2 section 1, which suggests a format of 8MIDxxxx, where the 8 designates handheld. Vsarious online source will tell you to drop the zero from the end of vessel MMSI and prefix with an 8. Neither the USCG HQ nor the FCC recognize this practice.

    It turns out that the FCC does have as "portable" license (for a fee) that can be linked to your federal record locator, which will have its own unique MMSI and Call Sign, You select it under the ULS system.

  • Thanks for the update! - But shame on the "authorities" for botching this REALLY BADLY. It seems NOBODY was thinking about this issue when the system was invented. :(

    I was thinking I might buy a DSC handheld this year - maybe I'll skip the hassle.

  • I just purchased a handheld VHF with DSC and wonder if there is any update on this topic of the best way to handle MMSI designation? I currently have one MMSI number that I use for the boat's primary VHF and AIS transceiver. It seems like it would be best to have a different number from the mothership for this portable radio.

  • I'm in the same position - just unwrapped and charged my SH HX870.
    I'd like to take it with me when i crew aboard a friend's Tartan 4300 from Annapolis to Haverstraw NY this week. Should I just use the same MMSI I have for the SH 2100 I installed on my own boat ( a little 24' Cornish Crabber) which is where I will use it most of the time or should I get a new MMSI from Boat US for the HX870?



    PS I think this has been answered in the past but I just searched Panbo and failed to find the answer.

  • Here's where the USCG explains that individual MMSI numbers are available for portable DSC VHF radios, except not here in the USA!

    "Obtaining MMSIs for DSC-equipped VHF Handhelds

    A handheld VHF transceiver with DSC and an integral global navigation satellite system (e.g. GPS) not intended for dedicated use on a particular ship (e.g. a diver’s radio) should be assigned a unique 9-digit number in the format 8MIDXXXXX. While currently means do not exist within the U.S. to assign such identities, the Coast Guard has been in discussions with the Federal communications Commission and others on implementing them.

    In the interim, VHF handhelds used in the United States should use the MMSI assigned to the ship to which the handheld is primarily associated, even if another radio on that ship uses the same MMSI. Non-commercial users of VHF handhelds not primarily associated with any single ship may use an MMSI provided by an organization such as BOAT US, SEA TOW and U.S. Power Squadron (see above). VHF handhelds should not be used ashore absent FCC or NTIA authorization allowing such use.

  • So if you get, say, a BoatUS MMSI assigned to very small boat and explain in the registration that it will be used with a handheld radio that may go anywhere on the water that you go, I do not believe that you will get in trouble. I've attended a meeting where the FCC and USCG both expressed frustration and embarrassment about this situation.

  • In my opinion, it is better to have the same mmsi # in both the fixed mount and handheld. When I got my HX870, I applied for a new Boat US # and programmed it in the 870. Then when I went to buddy boats to show them how the system worked, I would program their radio to call my 870 radio, so they could see how it works. Then I would need to edit my entry in their individual directory, as my fixed mount radio is on more of the time. Then, I got my 870 user mmsi # cleared and entered the same mmsi as my fixed mount. Problem solved. Both radios can call the other radio and the other radio answers perfectly (even though same mmsi #). I went one step further, on my 870, did "position report" to my same mmsi #, the chart plotter on my larger vessel showed the position of the handheld--EVERYTHING works perfectly.