MMSI numbers

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Jim Spence

Senior Member
Oct 6, 2007
Vessel Name
Sea Eagle
Vessel Make
Californian 50' Cockpit M/V
I decided recently that I needed to update the contact information associated with my MMSI number. My number is issued by the FCC because I have a radio operator license and station license. (required because I travel in the Carribean)

I went to the FCC database (I have an FRN (login)) and after about an hour decided I needed help changing the information. I sent an email to the FCC explaining the problem. Within 2 hours I got a phone call from the FCC and was emailed step by step instructions on how to change the information, As part of the phone call the young lady told me that I also needed to update the information with the Coast Guard.

I went to the Coast Guard site and didn't find anything about updating information on an existing MMSI number. So I did the logical thing, I emailed them using information found under "boating safety". I sent the following email: "I need to update the emergency contact information associated with my MMSI number."

I knew I was in trouble when the response was (and I quote) "What is an MMSI number?"

I spent the next 3 days emailing back and forth with at least 3 different people before I gave up. I was finally helped by a very nice young lady at BoatUS.

During this time I queried the international database to check what information they had.*** I do not show up in the database. I recently saw another boater on T & T who did not show up.

I recommend: If you have a DSC radio with an MMSI issued by the FCC. that you go to the following web site and see if you are there and if your information is correct.

According to the Coast Guard they*ONLY get their information from BoatUS and Sea Tow. The information is uploaded weekly. BoatUS and Sea Tow are only set up to issue*NEW numbers and only to nonFCC license holders. BoatUS went ahead and put me in their database with my existing number (I guess it has to be done by hand, not on the web site) and they sent an email to the FCC requesting that I be added to the ITU database. By the way the customer service that I got from BoatUS was outstanding.

I would be interested in hearing how many show up/don't show up in the ITU databse. If you have an FCC issued number you should be there. I have had my number since 2004 and it isn't there.

Anyone needing the FFC proceedure for updating info contact me off list.

-- Edited by Jim Spence at 05:54, 2008-02-02
Jim, I've had an FCC issued MMSI since around 1999.

It was properly listed on the ITU site.

Thanks for your work.
radio operator license

You mean there is a data base that still lists my old radio operator license (required in the 60's to fly) on some website?


I doubt if its still listed. Radio licenses expire after 10 years and have to be renewed.
I applied for a callsign and MMSI # via the FCC webiste in Oct 07 and have confirmed the record shows up in the ITU. db.*

I noticed a link to view and/or update the emergency contact info but a UID and PW are required for access.* Anyone know if the licensee is permitted to view/update?* If so, where do you reigster?* There wasn't an obvious link.* Thanks.

Makin Do
Poulsbo, WA
I applied for a callsign and MMSI # via the FCC webiste in Oct 07 and have confirmed the record shows up in the ITU. db.*

I noticed a link to view and/or update the emergency contact info but a UID and PW are required for access.* Anyone know if the licensee is permitted to view/update?* If so, where do you reigster?* There wasn't an obvious link.* Thanks.

Makin Do
Poulsbo, WA
Wht the heck are you guys talking about?*
So what is a MMSI number.* I may have or may need one and not kow it?
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MMSI numbers came into common usage with the availability of DSC (digital selective calling) radios. *MMSI stands for Maritime Mobile Service Identity. Heres how it works:* each vessel applies for an MMSI number that is unique to that vessel. *The same number is shared by all radios on board.* Acting somewhat like a phone number, the MMSI can be used to call a specific vessel (or even a group of vessels).**

Here is more info if you want to read about it.
The MMSI is also transmitted with an emergency call when you use the emergency button on your DSC enabled radio. This will Identify to the coast guard the information associated with your MMSI including boat name, length, description, and emergency contact information.
And if you feed your DSC radio with a GPS signal, it will automatically include your position in the emergency transmission when you hit the DSC button.
Is this the same number that is required for the AIS, automatic information system or is it different one? **I am not interest in the AIS as most of the boat/stuff/junk that are a concern will not have a AIS on board or attached.* **

* Not related to AIS. This is DSC which is a sort of "caller id" for your VHF. The MMSI is your personal number which shows up on the screen of a DSC VHF.

* You probably have plain old VHF radios in your boat which is why you are not familiar with this. The new VHF radios have a digital screen which shows the MMSI of people calling you (if they have DSC as well). It also shows your MMSI to people listening with DSC. With GPS connected it also shows you their location or them yours.

* This is a nice feature because you can actually call people privately by "paging" their MMSI instead of making a public broadcast to hail them on Ch 16. When they respond to the "page", both of your radios will automatically switch to a working channel. This cuts down on Ch16 traffic.

* During a crisis, you push a red panic button and the DSC VHF will automatically broadcast a MAYDAY with your MMSI id to everyone that has a DSC radio (including the USCG). This broadcast will have your information and distress message. If you connnect your DSC VHF to your GPS it will also broadcast your LAT/LON. You could send a Mayday with your info and location just by the press of a button. Much faster than speaking all the information over Ch16 and hoping someone hears it or understands it and much more accurate.
What happens if you are not registered, that is, that you have not filled out the MMSI forms and it becomes necessary to hit the panic button?* Are you ignored -- or what?

If you do not have an MMSI the red emergency button will still work. It will send out an alarm using VHF channel 70 which will be monitored by the CG. The CG will respond on VHF 16 asking something like "vessel calling emergency on DSC what is the nature of your distress?" Without an MMSI your "call" will not transmit any information about your vessel. Similarly, without connection of a GPS the emerency call will not provide the Coast Guard with your position.

I would encourage everyone to read their owners manuals and do some research on Digital Selective Calling (DSC). It is a great tool and well worth the time and effort.

To acquire an MMSI those in the US have two choices (1) acquire both a station license ($205 for 10 years) and a restricted operators license ($55 good for life) from the FCC or (2) apply for a free MMSI from BoatUS. The FCC version of an MMSI is required by law if you are communicating with foreign stations. If you are only using your radio in the US then you can get by with the free MMSI from BoatUS. But be aware.....the BoatUS MMSI is not distributed to foreign countries therefore critical info is not available to Canadian Coast Guard or any other nations you may be cruising through.

The FCC is accessible at The BoatUS free MMSI is at

That's the shortest, most concise, best and correct explanation of how DSC works that <u>I have ever read!</u> You just did one hell uv a service to this forum.* Thanks!
Let me second the reply from Seahorse II.* Good information, well presented.* Thanks.

While MMSI may eventually become a good system it seems like it still has a long way to go before it 'comes of age'.

For example, when I bought my current boat it had an MMSI capable radio installed. However, no one knows if it was ever programmed with information. It is not connected to the GPS. The manual has absolutely no information on how to reprogram with new information or to check if it has any old information.

It seems that the CG hasn't got a national or international organization plan. Canada hasn't got an international organization plan. Who's to say that anyone is really going to respond if it goes off anyway? I read from Steppens reply that if all the ducks and stars aren't lined up the CG is going to call you on 16 and ask for all the information anyway. Why not just push the 16 button and give them the info the old fashioned way?

I have attempted to get a station license for this boat. However after an hour of going from page to page on the FCC website I decided that the effort wasn't worth it. For example, you can't download the form, fill it out and send it in with a check. You have to fill out an additional form, a remittance form, in order to send them a check. AND, in multiple places it explains that if any forms are not filled out completly, or you don't fill out enough forms then you forfeit the funds sent in and have to start all over. This is government arrogance at its best. I choose not to play that game.

Am I taking a risk while in Canada? Maybe. But, it is the US law that states I need a station license to transmit outside the US. Will Canadian officials try to enforce US law? Probably not. And if someone was successfully prosecuted for not having a station license how long would it take for word to get out and hundreds of pleasure boaters would remove their "safety device" which is not required on a pleasure vessel?

I think MMSI is currently a feel good item. It makes those with MMSI radios feel like they have some protection and some extra help. I haven't heard any confirmation that it really worked for anyone yet. Are there success stories out there?

A friend took his boat to SE Alaska last summer in the company of two other boats. He told us that the DSC feature was great for staying in touch with the other boats.

They also had a mayday situation when they lost the water pump on their engine and the current and large waves began sending them toward shore. However they made their call on 16. The Canadian Coast Guard responded immediately and had a boat and a Canadian Auxilliary CG boat on the scene within minutes to tow them back to the nearby harbor. Once the situation had settled down they asked the CCG if they should have used the DCS button on the radio for the intial radio call, and the CCG said, no, 16 was just fine.
Thanks everyone for the compliments.

To Ken.the MMSI is only your station identifier. The technology we are talking about is DSC or Digital Selective Calling, which is a component of the USCG Rescue 21 program. Rescue 21 is installing DSC capability on all CG vessels and shore installations. The PNW is currently active as, I believe, is SE Alaska. The Canadian CG in British Columbia is also currently DSC capable. Most regions on the east coast are also up and running. To answer your specific comments:

1. If you have a DSC capable radio (i.e. it has a red emergency button) then you should be able to check the menu and/or setup function to see if there is an MMSI installed on the radio. If your owners manual doesnt adequately explain how to setup or access the DSC menus then I would suggest calling the manufacturers customer service people.
2. Not sure what organization plan you are referring to but the USCG and the CCG are both progressing towards full implementation of DSC. Both the US and Canadian CG in the PNW are currently up and running on DSC. For the US it is the USCGs Rescue 21 program.
3. The great advantage of using a DSC broadcast, with an MMSI installed and a connection to a GPS is that when you push that red emergency button it sends out a broadcast with your vessel information (name, owner, vessel type and size, etc) and your Lat/Long. You dont want to be standing at the helm having a heart attack and trying to send a mayday on 16 and reading out the lat and long to someone at the local Coast Guard District.
4. Also, a very important point is that in the future commercial vessels will no longer be required to monitor VHF 16. They will be required to monitor the DSC and whatever Vessel Traffic System they are operating within. This means that some of the tankers and cruise ships may very well not be listening for your mayday call on VHF 16. Thats why sending out the DSC digital alarm on VHF 70 is so important. Now, realistically, most all vessels in coastal waters will still be watching 16 (for liability reasons if no other) but I know for a fact that there are lots of tugs and fishing boats between here and Ketchikan that dont monitor 16, they are usually on 13 or some other channel.
5. You are right, the requirement for a station license is a US Federal Communications Commission requirement (actually I think it is a Federal statute) and realistically it is probably not enforced. So it is probably OK to take your chances. Using the FCC website is a major painit is not user friendly but if you call their 800 number they are quite ready to walk you through it all.
6. I have personally used DSC here in Washington and have monitored emergency transmissions from Canadian CG stations. I have not personally had to send out a mayday call using DSC (knock wood). I have used it for inter-ship and for security calls.
Good information Step, thanks. I do have a question though on point #3. How does pushing the red button tell the CG what the problem is? I can imagine that the response for a fire aboard, a sinking vessel and a medical emergency are all quite different.

My bet is that they are going to contact you on a voice channel and have you describe your situation whenever you push the red button. And, I would further bet that if you did not respond to the voice transmission they would send the most convenient unit to go take a look in a somewhat leisurely manner. For some reason I can't believe they will be mustering several units for an unknown problem from a pleasure boat.

So the radio will tx the basic information which is stored in the radio. How long will it be before the CG determines that many boats and radios have changed hands and the info is not up to date and they require confirmation of the information via voice?

If you've ever interacted with 911 you know that they confirm your name, address, phone number and what the problem is prior to sending anyone. Isn't DSC/MMSI the same type of system? 911 works very well on certain types of problems, but for most calls is only a convenience for the dispatcher in that they don't have to type the address into the dispatch screen.

Does the DSC information pop up and stay on your/my radio so that we could copy it down if we were in a position to assist? I presume that my radio would recieve the distressed vessels information, color, size, etc? Or is that only given to CG and then they relay?

Maybe you can clear this up for me. It is my understanding that commercial vessels are not required to monitor 16 under Inland rules already. If I understood correctly they are monitoring 13 and are only optionally monitoring 16. At least that is what Seattle Traffic advised when I was attempting to talk with a commercial vessel last summer.

I know, lot's of skeptical questions, but new technology needs to be proven to me before I totally trust it.

Ken Buck
Good questions, Ken.

Pushing the red button, with an MMSI installed and the GPS hooked to the radio will only send out an undesignated emergency alarm on VHF channel 70. Your radio will transmit the digital alarm briefly on 70 and then revert to 16. The CG will respond on 16 and, just like an all voice event, will ask the same questions. So essentially pushing the red button is a digital means of getting their attention and they will still need to talk to you.

I have an Uniden 525 VHF radio and I can either (a) use the red button to send an undesignated alarm with my MMSI and my lat/long or I can (b) select the DSC menu, select emergency and then select a designated emergency, like fire, sinking, injury, piracy etc. All DSC radios have the ability to send different types of messages, ship to ship, Pan Pan, all ships, position request etc. These other options are accessed through the DSC menu function, not the red button.

You are right about boats changing hands and not having current info programmed, and yes that could be problem. If I were to sell my boat I would darn well make sure I have erased my personal MMSI from the VHF before handing over the keys. I dont want to have someone else sending off my info to the CG. If I bought a new boat one of the first things I would do is to change the MMSI to a new one with my info. To do this some of the radios may need to be sent to the factory for reprogramming.

The only info that is going to pop up on your radio as a result of someone else sending an emergency DSC call is their MMSI number and their lat/long. You will not see their name, phone number or even a description of their boat. This last info is in a database and linked to the MMSI but it does not display on our VHF radios.

It is also my understanding that commercial traffic is only required to monitor 13 (bridge to bridge) or the Vessel Traffic (VTS) frequencies. In Puget Sound VHF 14 is south of Bush Point on Whidbey and VHF 5A is north of Bush Point and includes all of the Strait of Juan de Fuca and the San Juans. This is why DSC is so important. When you push that little red button it sends an alarm to ALL DSC EQUIPPED VESSELS on Channel 70 and then automatically switches their VHF to channel 16 and now everyone is listening to the emergency. If the commercial guys are only listening to 13 or 5A and you are out their broadcasting your mayday on 16 without using the DSC feature they will probably not hear you at all.

All fixed base VHF radios manufactured for sale in the US since 1997 have been required to be DSC capable. Very few handheld VHF radios have the DSC feature.
"This is why DSC is so important. When you push that little red button it sends an alarm to ALL DSC EQUIPPED VESSELS on Channel 70 and then automatically switches their VHF to channel 16 and now everyone is listening to the emergency."

Now there is a piece of information that is good to know. That might make it worth going thru what appears to be a hassle, worthwhile.

Ken Buck
I have a standard horizon VHF and Chart plotter. The Plotter will also show me where a DSC emergency came from or where someone I am talking to via their MMSI number is located. From there you can use the chart plotter functions to "goto" the location. It all should work very well. Notice I said should!
Steppen, as you say, commercial vessels required to have DSC radios have equipment that internally monitors Ch 70. So even though the VHF radio can be monitoring another channel (like 5A or 14), when a DSC broadcast is heard, the radio automatically switches to Ch 16.

If there is a MayDay broadcast on Ch 16 without a prior DSC activation, the CG or Vessel Traffic Service advises all relevant commercial vessels in the area of the MayDay to switch to Ch 16.
This thread got me thinking about my own DSC and MMSI situation so I googled the ITU and put in my EPIRB and MMSI numbers to see if they had me on record.They had <u>no record</u> of the number (MMSI) that I got from Boat US back in July. Anyone else had this problem and, if so, what did you do about it?

You have to get your number from the FCC to be in the ITU database. The assumption is that if you are traveling internationally you will have to have an FCC license for your radio equipment, therefore you have to get your MMSI from the FCC.
Boat US updates only the Coast Guard. I was told by both the Coast Guard and Boat US that the update takes place on a weekly basis.

-- Edited by Jim Spence at 19:25, 2008-02-18
Well, I think I started the quest to get into the ITU database on Feb 2. Last Wed I sent a second email to the FCC asking why I'm still not in the database. On Fri I recieved an email from the FCC that I would be in the next update to the ITU. (interesting enough the email was in response to my email of Feb 2nd.) I'll post another update when I actually show up.
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