Radio Regulations

Source: the Radio Regulations published by the International Telecommunication Union (ITU).

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Recommendation ITU-R M.541-11

Mandatory (1978-1982-1986-1990-1992-1994-1995-1996-1997-2004-2015-2023)

Operational procedures for the use of digital selective-calling equipment in the maritime mobile service

View official text at ITU

Version history

Version evolution

The number in each cell (e.g. −9) is the Recommendation's revision number — the “-9” in ITU-R M.585-9, not a negative value. So −8 → −9 means the binding reference moved from the 8th to the 9th revision.

RR-2008 -9
RR-2012 -9
RR-2016 -10
RR-2020 -10
RR-2024 -11

Incorporated into the RR by

RR provisions, footnotes and Resolutions that incorporate this Recommendation

Provision

51.35 52.112 52.149 52.153 54.2

Scope

The Recommendation contains the operational procedures for digital selective calling (DSC) equipment whose technical characteristics are given in Recommendation ITU-R M.493. The Recommendation contains six annexes. In Annexes 1 and 2 the provisions and procedures are described for distress, urgency and safety calls and for routine calls, respectively. In Annexes 3, 4, 5 and 6 the operational procedures for ships, for coast stations and man overboard (MOB) devices are described, and Annex 7 lists the frequencies to be used for DSC.

Keywords

Digital selective calling equipment operational procedures GMDSS distress alert

Recommends

  1. that the technical characteristics of equipment used for DSC in the maritime mobile service should be in conformity with the relevant ITU-R Recommendations;
  2. that the operational procedures to be observed in the MF, HF and VHF bands for DSC should be in accordance with Annex 1 for distress, urgency and safety calls and Annex 2 for other calls;
  3. that provisions should be made at stations equipped for DSC for:
  4. 3.1 the manual entry of address, type of call, category and various messages into a DSC sequence;
  5. 3.2 displaying the information in a user readable format;
  6. 3.3 the verification and, if necessary, the correction of such manually formed sequences;

+109 more in the full text

Related ITU-R Recommendations / Reports

Recommendations

  • ITU-R M.493 — – Digital selective-calling system for use in the maritime mobile service
  • ITU-R M.585 — – Assignment and use of identities in the maritime mobile service
  • ITU-R M.689 — – International maritime VHF radiotelephone system with automatic facilities based on DSC signalling format
  • ITU-R M.1082 — – International maritime MF/HF radiotelephone system with automatic facilities based on digital selective calling signalling format
  • ITU-R M.1171 — – Radiotelephony procedures in the maritime mobile service
  • ITU-R M.1371 — – Technical characteristics for an automatic identification system using time-division multiple access in the VHF maritime mobile band
  • ITU-R M.2135 — – Technical characteristics of autonomous maritime radio devices operating in the frequency band 156-162.05 MHz

Source: ITU Radio Regulations, editions of 2008, 2012, 2016, 2020 and 2024. The English, French and Spanish texts are each taken from the official edition in that language, not translated from one another. Sources and citation.