TELECOMMUNICATION CONVENTION. DECEMBER 9, 1932. shall be followed by the word DE and three transmissions of the call signal of the station sending it. It announces that this station is about to transmit a message concerning the safety of navigation or giving important meteorological warnings. [4311] (2) In radiotelephony, the word SECURITY (corre- sponding to the French pronunciation of the word" securit6") repeated three times, shall be used as the safety signal. [431] § 27. The safety signal and the message which follows it shall be transmitted on the distress wave or on one of the waves which, in some instances, may be used in case of distress (see § 3 of this article.) [438] § 28. (1) In the maritime mobile service, apart from messages transmitted according to a schedule, the safety signal must be trans- 2537 mitted toward the end of the first ensuing period of silence (art. 19, Ante, p. 2513. § 2), and the message shall be transmitted immediately after the period of silence; in the cases provided for in article 30, A, § 4 (3) and § 5 (1), Post, p. 2557. B, § 7, the safety signal and the message which follows it must be transmitted with as little delay as possible, but must be repeated, as has just been indicated, at the first ensuing period of silence. [439] (2) All stations hearing the safety signal must continue listening on the wave on which the safety signal has been sent until the message so announced has been completed; they must moreover keep silence on all waves likely to interfere with the message. [...,] (3) The foregoing rules shall be applicable to the aero- nautical service so far as they are not in conflict with regional arrange- ments providing aerial navigation with at least equivalent protection. ARTICLE 23 Working Hours oj Stations oj the Mobile Service [441] § 1. In order to permit the application of the rules indicated b~}~~ion working below regarding the hours of watch, each station of the mobile service must have an accurate clock and must take the necessary steps to sec that it is correctly adjusted to Greenwich mean time. A. LAND STATIONS [442] § 2. (1) The service of land stations shall, so far as possible, be continuous (day and night). However, the duration of the service of certain land stations may be limited. Each administration or public enterprise duly authorized to this effect, shall determine the service hours of the land stations under its authority. [443] (2) Land stations the service of which is not continuous may not close before having: 1. finished all operations called for by a distress call; I,and statiOll!l.
