ART54 – 72 – Section VII – Use of frequencies for data transmissions (WRC-12)52.263 B – Bands between 4 000 kHz and 27 500 kHz (WRC-12) B1 – Mode of operation of stations (WRC-12) MOD 52.264 The class of emissions to be used for data transmissions in this section should be in accordance with the most recent version of Recommendation ITU-R M.1798. Coast stations as well as ship stations should use radio systems specified in the most recent version of Recommendation ITU-R M.1798. (WRC-15) ARTICLE 54 Selective calling MOD 54.2 2) Selective calling is carried out using a digital selective calling system which shall be in accordance with Recommendation ITU-R M.541-10, and may be in accordance with the most recent version of Recommendation ITU-R M.493. (WRC-15) ARTICLE 57 Radiotelephony MOD 57.1 § 1 The procedure detailed in Recommendation ITU-R M.1171-0 shall be applicable to radiotelephone stations, except in cases of distress, urgency or safety. (WRC-15)