Source: [original on-line source is no longer available; please see an separate article that has information on how to access an archive of the GMDSS.COM.AU website.]The new version, 493-14, contains a number of important changes:
- Class D and E GMDSS systems (for recreational vessels) must be fitted with an integrated GPS receiver
- New Class H (handheld) - also must have integrated GPS
- New Class M (MoB) device - fitted with DSC and AIS
- the user interface requirements in Annex 3 have been made mandatory
There was also a general tidy up of paragraphs and tables.
The most interesting element of the revised recommendation is that CLASS-D DSC radios SHOULD have an integrated GPS or GNSS receiver, and CLASS-H handheld DSC radios MUST have an integrated GPS or GNSS receiver.
The newer ITU-R M.493-14 document can be obtained at no cost from the ITU website at
The recommendation is a very technical document, and not what one might call light reading.
In the United States, the Federal Communications Commission (FCC) is the regulating authority for marine radios. The FCC is presently requiring that radios sold for use in the USA must comply with the previous version of the recommendation, ITU-R M.493-13. I believe this is codified in the USC at 47 CFR 80.225 - Requirements for selective calling equipment. See https://www.law.cornell.edu/cfr/text/47/80.225 which says, in part:
Beginning March 25, 2009, the Commission will not accept new applications..for certification of non-portable [i.e. fixed-mount] DSC equipment that does not meet the requirements of ITU-R M.493-13 and, in the case of Class D DSC equipment only, IEC 62238.
As seen recently in their action against one major radio manufacturer (ICOM), the FCC has been quite strict in insisting on compliance. In some cases the offending practices in current-production radios were quite minor.
For example, ICOM was cited by the FCC (and fined) because their DSC radios did not comply with the requirements. Apparently one of the discrepancies found by the FCC in the ICOM radio was in regard to a requirement alerting the operator of the radio when the automatic position update information has become stale. The regulations say:
If the automatic position update is not available, a displayed and audible reminder to manually update the position should occur...before the position information is 4 hours old.
The out-of-compliance radio sounded the alarm at 4-hours; the remedy was to change the alarm to sound at 3-hours 59-minute, i.e., "before the position information is 4 hours old." By sounding the alarm one-second sooner, the radio complied with the recommendation. (Your government bureaucrats at work.)
There is no telling when and if the FCC will revise its regulations to adopt the new ITU recommendation. Perhaps it will be possible for the radio manufacturers to make new radios that comply with the new ITU recommendation and still have the radios comply with the old version, too. I don't know if such backwards compliance is possible.