INTERNATIONAL RADIO CONVENTION. NOVEMBER 25,1927. AR'I'lCLE 19 Distress, alarm, urgent and safety signals Distress signal §1. The distress signal shall consist of the group •.• __ _ ••• which indicates that the ship, aircraft, or other mobile station send- ing it, is threatened by grave and imminent danger, and requests immediate assistr1nce. Distress call §2. (1) Ti e distress call shall consist of the distress signal sent three times, followed by the word DE and the call signal of the mobile station in distress, sent three times. This call has absolute priority :wer all other transmissions. All mobile or land stations hearing it must immediately cease all transmissions capable of inter- fering with. the distress calls or messages and must listen on the wave used for t;le distress call. This call must not be addressed to a particular station. (2) The same rules apply to the radiotelephone distress call which consists of the spoken expression MAYDAY , (corresponding to the French pronunciation of the expression "m'aider" [help mel.) Distress message §3. The distress message shall include the distress call followed by the name of the ship, aircraft, or other mobile station in distress, and information concerning its position, the nature of the distress and the kind of assistance desired. §4. As a general rule and when a ship or aircraft on or over the sea is involved the position must be expressed in latitude and longi- tude (Greenwich) using figures for degrees and minutes, accompanied by one of the words NORTH or SOUTH, and by one of the words EAST or WEST. A period shall separate the degrees from the minutes, Where necessary, the true bearing and the distance in nautical miles from a known geographic point may be given. §5. The distress call and message shall be sent only by the authority of the master or person responsible for the ship, aircraft, or other mobile station. §6. A ship in distress shall transmit the distress call on the wave of 500 kc/s (600 m.), preferably of Type A2 or B. This call must be followed as soon as possible by the distress message. §7. The distress call and message must be repeated at intervals until an answer has been received, especially during the periods of silence specified in Article 17, section 2. The intervals must, how- ever, be long enough for stations preparing to reply to the. call to have time to start their sending apparatus. In the case where the ship in distress receives no answer to a distress call or message sent on the 500 kc/s (600 m.) wave, the call and the message may be repeated on any other available wave on which attention might be attracted. §8. Furthermore, a mobile station which is aware that another mobil9 station is in distress may transmit the distress message on condition that: (a) The station in distress is not itself in a position to transmit it. (b) The master (or his relief) of the vessel, aircraft, or other mobile station believes that further help is neceesary. 2869 Distress signal. Distress calL Distress message.
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