52.110 A – General
52.111 § 50 The provisions described in this Section are applicable to calling and acknowledgement, when digital selective-calling techniques are used, except in cases of distress, urgency and safety, to which the provisions of Chapter VII apply.
Band Maximum
mean power
4 MHz 5 kW
6 MHz 5 kW
8 MHz 10 kW
12 MHz 15 kW
16 MHz 15 kW
18/19 MHz 15 kW
22 MHz 15 kW
25/26 MHz 15 kW
52.112 § 51 The characteristics of the digital selective-calling equipment shall be in accordance with Recommendation ITU-R M.541-9 and should be in accordance with the most recent version of Recommendation ITU-R M.493. (WRC-07)
52.113 § 52 The frequencies on which coast stations provide services using digital selective-calling techniques shall be indicated in the List of Coast Stations and Special Service Stations (List IV), which shall also supply any other useful information concerning such services. (WRC-07)
52.114 B – Bands between 415 kHz and 526.5 kHz B1 – Mode of operation
52.115 § 53 1) The class of emission to be used for digital selective-calling and acknowledgement in the authorized bands between 415 kHz and 526.5 kHz shall be F1B.
52.116 2) When transmitting digital selective calls and acknowledgements in the bands between 415 kHz and 526.5 kHz, coast stations should use the minimum power necessary to cover their service area.
52.117 § 54 Transmissions of digital selective calls and acknowledgements by ship stations shall be limited to a mean power of 400 W.
B2 – Call and acknowledgement
52.118 § 55 For call and acknowledgement by digital selective-calling techniques, an appropriate channel shall be used.
52.119 § 56 The international digital selective-calling frequency 455.5 kHz may be assigned to any coast station. In order to reduce interference on this frequency, it may be used as a general rule by coast stations to call ships of another nationality, or in cases where it is not known on which digital selective-calling frequencies within these bands the ship station is maintaining watch.
52.120 § 57 The international digital selective-calling frequency 458.5 kHz may be used by any ship station. In order to reduce interference on this frequency, it shall only be used when calling cannot be made on national frequencies assigned to the coast station.
52.121 § 58 The frequency to be used for transmission of an acknowledgement shall normally be the frequency paired with the calling frequency used.
B3 – Watch
52.122 § 59 1) A coast station providing international public correspondence service using digital selective-calling techniques within the bands between 415 kHz and 526.5 kHz should, during its hours of service, maintain automatic digital selective-calling watch on appropriate national or international selective-calling frequencies. The hours and frequencies shall be indicated in the List of Coast Stations and Special Service Stations (List IV). (WRC-07)
52.123 2) Ship stations equipped with apparatus for digital selective-calling to work in the authorized bands between 415 kHz and 526.5 kHz should, when within the coverage area of coast stations providing services using digital selective-calling techniques in these bands, maintain an automatic digital selective-calling watch on one or more appropriate digital selective-calling frequencies within these bands, taking into account the digital selective-calling frequencies operated by the coast stations.
52.124 C – Bands between 1 606.5 kHz and 4 000 kHz (WRC-03)
C1 – Mode of operation
52.125 § 60 1) The class of emission to be used for digital selective-calling and acknowledgement in the bands between 1 606.5 kHz and 4 000 kHz shall be F1B. (WRC-03)
52.126 2) Coast stations should, when transmitting digital selective calls and acknowledgements in the bands between 1 606.5 kHz and 4 000 kHz, use the minimum power necessary to cover their service area. (WRC-03)
52.127 3) In Region 1, transmissions of digital selective calls and acknowledgements by ship stations shall be limited to a mean power of 400 W.
C2 – Call and acknowledgement
52.128 § 61 1) When calling a coast station by digital selective-calling techniques, ship stations should use for the call, in order of preference:
52.129 a) a national digital selective-calling channel on which the coast station is maintaining watch;
52.130 b) subject to the provisions of No. 52.131, the international digital selective-calling frequency 2 189.5 kHz.
52.131 2) The international digital selective-calling frequency 2 189.5 kHz may be assigned to any ship station. In order to reduce interference on this frequency, it may be used as a general rule by ship stations to call coast stations of another nationality.
52.132 3) A ship station calling another ship station by digital selective-calling techniques should use the frequency 2 177 kHz for the call. Acknowledgements of such calls should also be made on this frequency.
52.133 § 62 1) When calling ship stations by digital selective-calling techniques, coast stations should use for the call, in the order of preference:
52.134 a) a national digital selective-calling channel on which the coast station is maintaining watch;
52.135 b) subject to the provisions of No. 52.136, the international digital selective-calling frequency 2 177 kHz.
52.136 2) The international digital selective-calling frequency 2 177 kHz may be assigned to any coast station. In order to reduce interference on this frequency, it may be used as a general rule by coast stations to call ships of another nationality, or in cases where it is not known on which digital selective-calling frequencies within the bands between 1 606.5 kHz and 4 000 kHz the ship station is maintaining watch. (WRC-03)
52.137 § 63 The frequency to be used for transmission of an acknowledgement shall normally be the frequency paired with the frequency used for the call received, as indicated in the List of Coast Stations and Special Service Stations (List IV) (see also No. 52.113). (WRC-07)
C3 – Watch
52.138 § 64 1) The provisions detailed in this Sub-section are applicable to watch-keeping by digital selective-calling, except for distress, urgency and safety purposes, to which the provisions of Section III of Article 31 apply.
52.139 2) A coast station providing international public correspondence service using digital selective-calling techniques within the bands between 1 606.5 kHz and 4 000 kHz should, during its hours of service, maintain automatic digital selective-calling watch on appropriate national or international selective-calling frequencies. The hours and frequencies shall be indicated in the List of Coast Stations and Special Service Stations (List IV). (WRC-07)
52.140 3) Ship stations equipped with apparatus for digital selective-calling to work in the authorized bands between 1 606.5 kHz and 4 000 kHz should, when within the coverage area of coast stations providing services using digital selective-calling techniques in these bands, maintain an automatic digital selective-selective-calling watch on one or more appropriate digital selective-calling frequencies within these bands, taking into account the digital selective-calling frequencies operated by the coast stations. (WRC-03)
52.141 D – Bands between 4 000 kHz and 27 500 kHz
D1 – Mode of operation
52.142 § 65 1) The class of emission to be used for digital selective-calling and acknowledgement in the authorized bands between 4 000 kHz and 27 500 kHz shall be F1B.
52.143 2) When transmitting digital selective calls and acknowledgements in the bands between 4 000 kHz and 27 500 kHz, coast stations shall at no time use a mean power in excess of the following values:
52.144 3) Transmissions of digital selective calls and acknowledgements by ship stations in the bands between 4 000 kHz and 27 500 kHz shall be limited to a mean power of 1.5 kW.
D2 – Call and acknowledgement
52.145 § 66 A station calling another station by digital selective-calling techniques within the authorized bands between 4 000 kHz and 27 500 kHz should choose an appropriate digital selective-calling frequency, taking into account propagation characteristics.
52.146 § 67 1) When calling a coast station by digital selective-calling techniques on frequencies within the authorized bands between 4 000 kHz and 27 500 kHz, ship stations should use for the call, in order of preference:
52.147 a) a national digital selective-calling channel on which the coast station is maintaining watch;
Band Maximum
mean power
4 MHz 5 kW
6 MHz 5 kW
8 MHz 10 kW
12 MHz 15 kW
16 MHz 15 kW
18/19 MHz 15 kW
22 MHz 15 kW
25/26 MHz 15 kW
52.148 b) subject to the provisions of No. 52.149, one of the international digital selective-calling frequencies. (WRC-07)
52.149 2) The international digital selective-calling frequencies shall be as indicated in Recommendation ITU-R M.541-9 and may be used by any ship station. In order to reduce interference on these frequencies, they shall only be used when calling cannot be made on nationally assigned frequencies. (WRC-07)
52.150 § 68 1) When calling ship stations by digital selective-calling techniques on frequencies within the bands between 4 000 kHz and 27 500 kHz coast stations should use for the call, in order of preference:
52.151 a) a national digital selective-calling channel on which the coast station is maintaining watch;
52.152 b) subject to the provisions of No. 52.153, one of the international digital selective-calling frequencies. (WRC-07)
52.153 2) The international digital selective-calling frequencies shall be as indicated in Recommendation ITU-R M.541-9 and may be assigned to any coast station. In order to reduce interference on these frequencies, they may be used as a general rule by coast stations to call ships of another nationality, or in cases where it is not known on which digital selective-calling frequencies within the bands concerned the ship station is maintaining watch. (WRC-07)
D3 – Watch
52.154 § 69 1) The provisions detailed in this Sub-section are applicable to watch-keeping by digital selective-calling, except for distress, urgency and safety purposes, to which the provisions of Section III of Article 31 apply.
52.155 2) A coast station providing international public correspondence service using digital selective-calling techniques within the bands between 4 000 kHz and 27 500 kHz should, during its hours of service, maintain automatic digital selective-calling watch on the appropriate digital selective-selective-calling frequencies as indicated in the List of Coast Stations and Special Service Stations (List IV). (WRC-07)
52.156 3) Ship stations equipped with apparatus for digital selective-calling to work in the authorized bands between 4 000 kHz and 27 500 kHz should maintain automatic digital selective-calling watch on appropriate digital selective-calling frequencies within these bands, taking into account propagation characteristics and the calling frequencies for coast stations providing service using digital selective-calling techniques.
52.157 E – Bands between 156 MHz and 174 MHz E1 – Mode of operation
52.158 § 70 The class of emission to be used for digital selective-calling and acknowledgement in the authorized bands between 156 MHz and 174 MHz shall be G2B.
E2 – Call and acknowledgement
52.159 § 71 1) The frequency 156.525 MHz is an international frequency in the maritime mobile service used for distress, urgency, safety and calling by digital selective-calling techniques (see Nos. 33.8 and 33.31 and Appendix 15). (WRC-07)
52.160 2) Calling by digital selective-calling techniques within the authorized bands between 156 MHz and 174 MHz, from ship to coast station, from coast station to ship and from ship to ship should, as a general rule, be made on the digital selective-calling frequency 156.525 MHz.
E3 – Watch
52.161 § 72 Information concerning watch-keeping by automatic digital selective-calling on the frequency 156.525 MHz by coast stations shall be given in the List of Coast Stations and Special Service Stations (List IV) (see also No. 31.13). (WRC-07)
52.162 § 73 Ship stations equipped with apparatus for digital selective-calling to work in the authorized bands between 156 MHz and 174 MHz should, while at sea, maintain an automatic digital selective-calling watch on the frequency 156.525 MHz (see also No. 31.17).
Section V – Use of frequencies for wide-band telegraphy, facsimile, special transmission systems and oceanographic data transmissions
52.163 A – Wide-band telegraphy, facsimile and special transmission systems 52.164 A1 – Bands between 1 606.5 kHz and 4 000 kHz (WRC-03)
52.165 § 74 In Region 2, the frequencies in the band 2 068.5-2 078.5 kHz are assigned to ship stations using wide-band telegraphy, facsimile and special transmission systems. The provisions of No. 52.171 apply.
52.166 A2 – Bands between 4 000 kHz and 27 500 kHz
52.167 § 75 In all bands, the working frequencies for ship stations equipped to use wide-band telegraphy, facsimile and special transmission systems are spaced 4 kHz apart. The assignable frequencies are shown in Appendix 17.
52.168 § 76 1) Each administration shall assign to each ship station under its jurisdiction and employing wide-band telegraphy, facsimile and special transmission systems one or more series of the working frequencies reserved for this purpose shown in Appendix 17. The total number of series assigned to each ship station shall be determined by traffic requirements.
52.169 2) When ship stations employing wide-band telegraphy, facsimile and special transmission systems are assigned less than the total number of working frequencies in a band, the administration concerned shall assign working frequencies to such ships in accordance with an orderly system of rotation that will ensure approximately the same number of assignments on any one working frequency.
52.170 3) However, within the limits of the bands given in Appendix 17, administrations may, to meet the needs of specific systems, assign frequencies in a different manner from that shown in Appendix 17. Nevertheless administrations shall take into account, as far as possible, the provisions of Appendix 17, concerning channelling and the 4 kHz spacing.
52.171 § 77 Ship stations equipped for wide-band telegraphy, facsimile and special transmission systems may, in the frequency bands reserved for such use, employ any class of emission provided that such emissions can be contained within the wide-band channels indicated in Appendix 17. However, the use of A1A Morse telegraphy and telephony is excluded except for circuit alignment purposes.
52.172 § 78 Coast radiotelegraph stations employing multichannel telegraph emissions and operating in the bands allocated exclusively to the maritime mobile service between 4 000 kHz and 27 500 kHz shall at no time use a mean power in excess of 2.5 kW per 500 Hz bandwidth.
52.173 B – Oceanographic data transmission systems
52.174 § 79 In all bands, the assignable frequencies for oceanographic data transmissions are spaced 0.3 kHz apart. The assignable frequencies are shown in Appendix 17.
52.175 § 80 The frequency bands for oceanographic data transmission systems (see Appendix 17) may also be used by buoy stations for oceanographic data transmission and by stations interrogating these buoys.