Maritime Mobile Service Identity
Encyclopedia
A Maritime Mobile Service Identity (MMSI) is a series of nine digits which are sent in digital form over a radio frequency
channel in order to uniquely identify ship stations, ship earth station
s, coast stations, coast earth stations, and group calls. These identities are formed in such a way that the identity or part thereof can be used by telephone and telex subscribers connected to the general telecommunications network to call ships automatically.
There are now six kinds of maritime mobile service identities:
assigned to each country is written in Table 1 ITU
Radio Regulations Appendix 43.
where MID represent the Maritime Identification Digits and X is any figure from 0 to 9.
If the ship is fitted with an Inmarsat B, C or M ship earth station, or it is expected to be so equipped in the foreseeable future, then the identity should have three trailing zeros:
If the ship is fitted with an Inmarsat C ship earth station, or it is expected to be so equipped in the foreseeable future, then the identity could have one trailing zero:
If the ship is fitted with an Inmarsat A ship earth station, or has satellite equipment other than Inmarsat, then the identity needs no trailing zero.
where the first figure is zero and X is any figure from 0 to 9. The particular MID represents only the country assigning the group ship station call identity and so does not prevent group calls to fleets containing more than one ship nationality.
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where the first two figures are zeros and X is any figure from 0 to 9. The MID reflects the country in which the coast station or coast earth station is located.
where the first two figures are zeros and X is any figure from 0 to 9.
, federal MMSIs are assigned by the National Telecommunications and Information Administration
, and are normally, but not always, formed as 3669XXXXX. Non federal MMSIs are assigned by the Federal Communications Commission
normally as part of the ship station license application, and are formed as 366XXX000 for ships on international voyages and ships needing an Inmarsat mobile earth station, or 366XXXXX0 for all other ships.
The United States Coast Guard
group ship station call identity is 036699999, and group coast station call identity is 003669999.
In the U.S., MMSIs are primarily used for digital selective calling and for assigning Inmarsat identities.
The problem exists with Inmarsat-equipped ships because ITU-T recommendations require that Inmarsat ship earth stations be assigned the identity (MESIN) TMIDXXXYY, where T indicates the type of Inmarsat station, YY indicates the Inmarsat station extension (e.g."00" might indicate a telephone in the bridge, "01" might indicate a fax machine in the radio room, etc.), and MIDXXX indicates the ship station number, which relates to the assigned ship station identity MIDXXX000.
The MMSI was meant to be an all-inclusive ship electronic identity, used in one form or another by every GMDSS or telecommunications instrument on the ship. Questions have been raised, however, whether the MMSI can in practice totally fulfill that role. ITU may eventually end the practice of relating Inmarsat MESIN identities with the ship MMSI identity.
The World Radio Conference, Geneva, 1997 (WRC-97), adopted Resolution 344 concerning the exhaustion of the maritime mobile service identity resource. In view of improvements to public switched telephone network
s, and new capabilities of the Inmarsat system other than Inmarsat B or M, previous restrictions should no longer be applicable. All nine digits of the MMSI can be used in such cases, and no longer need to end in trailing zeros.
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
channel in order to uniquely identify ship stations, ship earth station
Earth station
A ground station, earth station, or earth terminal is a terrestrial terminal station designed for extraplanetary telecommunication with spacecraft, and/or reception of radio waves from an astronomical radio source. Ground stations are located either on the surface of the Earth, or within Earth's...
s, coast stations, coast earth stations, and group calls. These identities are formed in such a way that the identity or part thereof can be used by telephone and telex subscribers connected to the general telecommunications network to call ships automatically.
There are now six kinds of maritime mobile service identities:
- Ship station identities,
- Group ship station identities,
- Coast station identities,
- Group coast station identities.
- SAR aircraft
- Navigational aids and craft associated with a parent ship
The first digit of an MMSI
The initial digits of an MMSI categorize the identity. The meaning of the first digit is:- 0 Ship group, coast station, or group of coast stations
- 1 Recently re-assigned for use by SAR aircraft (ITU-R recommendation M.585-4)
- 2-7 MMSI's used by individual ships, beginning with an MID (see below)
- 2 Europe
- 3 North and Central America and Caribbean
- 4 Asia
- 5 Oceana
- 6 Africa
- 7 South America
- 8 Assigned for regional Use
- 9 Recently re-assigned to Nav aids and also craft associated with a parent ship (ITU-R recommendation M.585-4)
Maritime identification digits (MID)
An MID consists of 3 digits, always starting with a digit from 2 to 7 (assigned regionally). A second MID can be assigned once the MID first or subsequently allocated is more than 80% exhausted and the rate of assignments is such that 90% exhaustion is foreseen. A listing of MIDsMaritime identification digits
Maritime identification digits are used by radio communication facilities to identify their home country or base area in Digital Selective Calling and Automatic Identification System messages, as part of their Maritime Mobile Service Identities. The International Telecommunication Union...
assigned to each country is written in Table 1 ITU
Itu
Itu is an old and historic municipality in the state of São Paulo in Brazil. The population in 2009 was 157,384 and the area is 641.68 km². The elevation is 583 m. This place name comes from the Tupi language, meaning big waterfall. Itu is linked with the highway numbered the SP-75 and are flowed...
Radio Regulations Appendix 43.
Ship station identities
The 9-digit code constituting a ship station identity is formed as follows:- MIDXXXXXX
where MID represent the Maritime Identification Digits and X is any figure from 0 to 9.
If the ship is fitted with an Inmarsat B, C or M ship earth station, or it is expected to be so equipped in the foreseeable future, then the identity should have three trailing zeros:
- MIDXXX000
If the ship is fitted with an Inmarsat C ship earth station, or it is expected to be so equipped in the foreseeable future, then the identity could have one trailing zero:
- MIDXXXXX0
If the ship is fitted with an Inmarsat A ship earth station, or has satellite equipment other than Inmarsat, then the identity needs no trailing zero.
Group ship station call identities
Group ship station call identities for calling simultaneously more than one ship are formed as follows:- 0MIDXXXXX
where the first figure is zero and X is any figure from 0 to 9. The particular MID represents only the country assigning the group ship station call identity and so does not prevent group calls to fleets containing more than one ship nationality.
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Coast station identities
Coast station identities are formed as follows:- 00MIDXXXX
where the first two figures are zeros and X is any figure from 0 to 9. The MID reflects the country in which the coast station or coast earth station is located.
Group coast station call identities
Group coast station call identities for calling simultaneously more than one coast station are formed as a subset of coast station identities, as follows:- 00MIDXXXX
where the first two figures are zeros and X is any figure from 0 to 9.
In the United States
In the U.S.United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, federal MMSIs are assigned by the National Telecommunications and Information Administration
National Telecommunications and Information Administration
The National Telecommunications and Information Administration is an agency of the United States Department of Commerce that serves as the President's principal adviser on telecommunications policies pertaining to the United States' economic and technological advancement and to regulation of the...
, and are normally, but not always, formed as 3669XXXXX. Non federal MMSIs are assigned by the Federal Communications Commission
Federal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
normally as part of the ship station license application, and are formed as 366XXX000 for ships on international voyages and ships needing an Inmarsat mobile earth station, or 366XXXXX0 for all other ships.
The United States Coast Guard
United States Coast Guard
The United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...
group ship station call identity is 036699999, and group coast station call identity is 003669999.
In the U.S., MMSIs are primarily used for digital selective calling and for assigning Inmarsat identities.
Exhaustion of MMSIs
Because all ships on international voyages, as well as all ships fitted with an Inmarsat B or M ship earth station, are assigned MMSIs of the format MIDXXX000, a serious problem has arisen internationally in assigning sufficient numbers of MIDs to all administrations that need them. For example, a country having 10,000 Inmarsat-equipped ships would require 10 MIDs just to accommodate those 10,000 ships. If 50,000 boaters decided to fit small Inmarsat M terminals, 50 additional MIDs would be required to accommodate them.The problem exists with Inmarsat-equipped ships because ITU-T recommendations require that Inmarsat ship earth stations be assigned the identity (MESIN) TMIDXXXYY, where T indicates the type of Inmarsat station, YY indicates the Inmarsat station extension (e.g."00" might indicate a telephone in the bridge, "01" might indicate a fax machine in the radio room, etc.), and MIDXXX indicates the ship station number, which relates to the assigned ship station identity MIDXXX000.
The MMSI was meant to be an all-inclusive ship electronic identity, used in one form or another by every GMDSS or telecommunications instrument on the ship. Questions have been raised, however, whether the MMSI can in practice totally fulfill that role. ITU may eventually end the practice of relating Inmarsat MESIN identities with the ship MMSI identity.
The World Radio Conference, Geneva, 1997 (WRC-97), adopted Resolution 344 concerning the exhaustion of the maritime mobile service identity resource. In view of improvements to public switched telephone network
Public switched telephone network
The public switched telephone network is the network of the world's public circuit-switched telephone networks. It consists of telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables, all inter-connected by...
s, and new capabilities of the Inmarsat system other than Inmarsat B or M, previous restrictions should no longer be applicable. All nine digits of the MMSI can be used in such cases, and no longer need to end in trailing zeros.
See also
- Call signCall signIn broadcasting and radio communications, a call sign is a unique designation for a transmitting station. In North America they are used as names for broadcasting stations...
- Automatic Identification SystemAutomatic Identification SystemThe Automatic Identification System is an automatic tracking system used on ships and by Vessel traffic services for identifying and locating vessels by electronically exchanging data with other nearby ships and AIS Base stations...
- Global Maritime Distress Safety SystemGlobal Maritime Distress Safety SystemThe Global Maritime Distress and Safety System is an internationally agreed-upon set of safety procedures, types of equipment, and communication protocols used to increase safety and make it easier to rescue distressed ships, boats and aircraft....
External Links
- MARITIME MOBILE SERVICE IDENTITY (MMSI), UCSG, which was adapted from Appendix 43 of the International Telecommunications Union Radio Regulations
- Table of MIDs from ITU
- BoatUS offers a free US-only recreational boater MMSI registration, as well as tutorials and a useful FAQ.