li: STAT.] MULTILATEIlAL-TELIEC'()MMUNI('ATIONS-O()CT. 2 . 1947 (Chapter XIV, arL. 37 IK) (940-947 940 § 38. (1) Mobile stations which hear the urgency signal must continue to listen for at least three minutes. At the end of this period, if no urgency message has been heard, they may re- sume their normal service. 941 (2) However, land and mobile stations which are in communication on frequencies other than those used for the transmission of the urgency signal and of the call which follows it may continue their normal work without interrup- tion provided the urgency message is not addressed "to all stations" (CQ). 942 § 39. When the urgency signal has been sent before transmitting a message which is intended for all stations and which calls for action by the stations receiving the message, the station responsible for its transmission must cancel it as soon as it knows that action is no longer necessary. This mes- age of cancellation must likewise be addressed "to all stations" (CQ). Section XI. Safety Signal 943 § 40. (1) In radiotelegraphy, the safety signal consists of three repetitions of the group TTT, sent with the letters of each group and the successive groups clearly separated from each other. It is sent before the call. 944 (2) In radiotelephony, the word S!CURITPi pro- nounced as the French word "securite", repeated three times, is used for the safety signal. 945 § 41. (1) The safety signal indicates that the station is about to transmit a message concerning the safety of navigation or giving important meteorological warnings. 946 (2) The safety signal and the message which follows it are sent on the distress frequency or on one of the fre- quencies which may be used in case of distress (see 868 to 871). 917 § 42. (1) With the exception of messages transmitted at fixed times, the safety signal, when it is used in the maritime mobile service, must be transmitted towards the end of the first 1921
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