38 Proceedings | Vol. 83, No. 1 ITU radio regulations require every radio-equipped ship to have a ship station radio license maintained by the flag state’s telecommunications authority. Every ship station license was already required to include vessel identity and the owner’s contact information, which could become the basis of an existing distress alert iden- tity database accessible by SAR authorities. Since ITU has regulatory authority over ship station licenses, adapting it to the needs of DSC and SAR authorities has been a straightforward process. In 1982, ITU chose to use the existing ship station license as its identity database, creating a new nine-digit identity, a digital radio call sign—the Maritime Mobile Service Identity, or MMSI. Assigned by ITU, the first three digits of the MMSI, the Maritime Identification Digits (MID), identify the administration or nation responsible for licensing the radio. The United States was assigned MIDs 338, 366, 367, 368, and 369. The remaining six digits are assigned to individual ships by each nation’s tele- communications authority, which in the United States is the Federal Communications Commission (FCC). MMSIs have the same legal status as radio call signs. Every radio station license, be it a ship station, coast station, or TV and radio broadcast station license, has a radio call sign identifying the transmitted radio sig- nal and authorizing that radio to transmit. Every ship equipped with a DSC radio must have a ship station license, and that license must include the ship’s assigned radio call sign and as well as its MMSI. How MMSIs were Implemented in the United States The FCC Wireless Telecommunications Bureau is responsible for managing MMSIs in the United States. MMSIs, automatically assigned during the application and licensing process when filing for a station license with the FCC,6 are maintained by the FCC’s Universal Licensing System database, which routinely updates its information to the Coast Guard’s MISLE database. Coast Guard SAR watch standers receiving a DSC distress call can access this MISLE database anytime to identify the distressed vessel and owner contact information. While a ship station license is an international man- date affecting every country, Congress allows the FCC more flexibility in licensing recreational boaters. In 1996, while MMSIs were beginning to be assigned and used in the United States, the FCC authorized ship radio stations that operate domestically, but are not required by statute or treaty to carry a radio, to operate without individual licenses, also known as license-by-rule.7 This primar- ily affected radio-equipped recreational boats and their owners, possibly the largest group of DSC users. Here’s where MMSI registration in the United States deviates from procedures in the rest of the world. Since previously mandatory FCC licenses had been how boaters obtained MMSIs, simpler means of issuing MMSIs needed to be found for recreational vessels that were not required to obtain a license. Beginning in 2000, the FCC and Coast Guard established Memorandums of Understanding authorizing license-by-rule providers to assign MMSIs to recreational boaters at reasonable rates, and to routinely provide MMSI registration data to the Coast Guard. These authorized license-by-rule8 provid- ers included BOAT US, US Power Squadrons, and Shine Micro.9 Why 60% of DSC Distress Alert Identity Information is Unusable in the United States For vessels required to obtain a license, FCC ship station license regulations ensure an MMSI is issued. But MMSI regulations for vessels licensed-by-rule, which do not need an individual license, are not so clear. Unknown to many recreational boaters, an extra step is required to obtain an MMSI.10 When recreational boaters install a new radio and are instructed to enter a nine-digit number to complete activation, many make up a number rather than entering a correctly registered MMSI. The MMSI requirement for radios licensed by rule does exist in FCC regulations, but it is not clearly stated. The Radio Technical Commission for Maritime Services (RTCM), with the cooperation of the Coast Guard, petitioned the FCC in 2016 with a proposal to update its maritime regulations, which would clarify MMSI requirements. While that action is still pending, the FCC has issued a Public Notice attempting to clarify this.11 Once a wrong MMSI number is entered, it is very difficult to fix. Most radio manufacturers allow users three attempts to enter their MMSI. Once entered, the user cannot change it without removing the radio and shipping it to an authorized representative or arranging for an authorized representative to visit the vessel, and both options are costly. ITU regulations cause this difficulty by stating that “Once stored, it should only be possible for an autho- rized user to change the MMSI with advice/cooperation from the manufacturer.”1 Resolving These Unusable Distress Alert MMSI Identity Problems Simplifying the reset process In 2025, RTCM adopted Standard 10160.0, Procedures for the Resetting of Own-Ship Maritime Mobile Service Identities (MMSIs) on DSC Marine Radios and Setting and Resetting Static Data on Automatic Identification Systems (AIS). This standard is intended to significantly simplify resetting own-ship MMSIs and AIS static data to the factory default. The new procedures allow for
