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• ship stations for working in Morse telegraphy;
• ship stations (non-paired) for NBDP telegraphy and data transmission systems at
speeds not exceeding 100 Bd for FSK and 200 Bd for PSK and for Morse
telegraphy (working);
• ship stations for DSC;
• coast stations (paired) for NBDP telegraphy and data transmission systems at
speeds not exceeding 100 Bd for FSK and 200 Bd for PSK;
• coast stations for DSC;
• coast stations wide-band and Morse telegraphy, facsimile, special and data
transmission systems and NBDP telegraphy;
• coast stations for telephony, duplex operation;
• initial testing and the possible future introduction within the maritime service of
new digital technologies (Appendix 17to the RR, Part A, note p to the table).
Appendix 25 to the Radio Regulations contains the provisions and the associated
frequency allotment Plan for coast radiotelephone stations operating in the exclusive
maritime mobile bands between 4 000 kHz and 27 500 kHz.
There are a number frequencies used for distress and safety communications in the
GMDSS in the 4, 6, 8, 12, 16, 18/19, 22 and 25/26 MHz bands. Details of their use are
specified in Appendix 15 to the Radio Regulations.
Other MSI broadcasts for ships at greater ranges are transmitted from the UK on the
following frequencies in the HF bands, termed high sea NBDP MSI transmissions from
coast stations – 4210 kHz, 6314 kHz, 8416.5 kHz and 12579 kHz.
The frequencies used for non-GMDSS distress and safety communications are: 4125,
6215 and 8364 kHz; details of their use are specified in Appendix 13 to the Radio
Regulations.
From the United Kingdom perspective there is no congestion in those HF bands used for
commercial traffic (see also Section 6.7.3).
6.7.2 Technology Description
• Morse telegraphy, class of emission A1A;
• narrow-band direct printing, class of emission F1B or J2B;
• digital selective calling (DSC), class of emission F1B or J2B;
• single-sideband telephony, class of emission J3E, simplex and duplex operation;
• narrow and wideband data transmission, class of emission F1B or J2B.
The technology used ranges from Morse telegraphy, to more advanced systems, such as
DSC, NBDP and wideband data transmission. Due to the international character of the
service, progress in implementing more modern techniques on a worldwide basis is slow.
Technical characteristics of the equipment can be found in Recommendation ITU-R
M.476 for NBDP (incorporated by reference in the RR), in Recommendation ITU-R M.493
for DSC, in Recommendation ITU-R M.625 for NBDP equipment employing automatic
identification (incorporated by reference in the RR), in Recommendation ITU-R M.627 for
NBDP equipment using NBPSK (incorporated by reference in the RR), in
Recommendation ITU-R M.688 for direct-printing telegraph systems for promulgation of
high seas and NAVTEX-type safety information, in Recommendation ITU-R M.1081 for
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