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Commercial Radio Operator License Program


GMDSS Radio Maintainer's License (DM)


The DM qualifies personnel as GMDSS radio maintainers to perform at sea repair and maintenance of GMDSS equipment. It also confers the operating authority of the PG and MP.

NOTE: In instances where an applicant qualifies for both a DO and a DM, the applicant qualifies to hold a GMDSS Radio Operator/Maintainer License (DB).


To qualify, you must:

Term of License

A DM is issued for the holder's lifetime. (Prior to March 25, 2008, the license term for a DM was five years. Any holder of a DM that expired prior to March 25, 2008, must still file an application to renew the license within the five-year grace period after expiration.)

How to Obtain a License

Submit FCC Form 605 along with the appropriate Proof of Passing Certificates (for the requisite written examination elements). Use the FCC Form 605 and the FCC Form 159 (fee processing form) to renew a license or to replace a lost, stolen, or mutilated license. Many Commercial Operator License Examination (COLE) Managers file these documents for applicants who test with them. Ask your COLEM if it provides this service to its customers.


To obtain an FCC Commercial Operator License, applicants must submit, to the Commission, proof of passing written Elements as illustrated in the following table.

View License Comparison Chart Written Elements Telegraphy Elements
Type of License 1 3 5 6 7 7R 8 9 1 2
GMDSS Radio Maintainer's License Check Mark Check Mark Check Mark

Written Examination Elements

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