Page:United States Statutes at Large Volume 49 Part 2.djvu/517

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TELECOMMUNICATION CONVENTION. DECEMBER 9, 1932. 2533 ['1'] (3) A station which repeats a distress call or a distress message shall transmit after it the word DE followed by its own call signal three times. I. AUTOMATIC ALARM SIGNAL ['17] § 21. (1) The alarm signal shall consist of a series of 12 dashes Ds-(utomaticaJarmsig. sent in 1 minute, the duration of each dash being 4 seconds and the duration of the interval between 2 dashes, 1 second. It can be trans- mitted by hand or by means of an automatic instrument. ['18] (2) The only purpose of this special signal is to set into operation the automatic apparatus used to give the alarm. It must only be used either to announce that a distress call or message is to follow, or to announce the transmission of an urgent cyclone warning; in the latter case it can only be used by coast stations duly authorized by their government. [4UI) (3) In cases of distress, the use of the alarm signal is indicated in § 5 (1); in the case of urgent cyclone warnings, the emission of this warning must begin only 2 minutes after the end of the alarm signal. [420) (4) The automatic instruments intended for the recep- tion of the alarm signal must satisfy the following conditions: 1. they must be set into operation by the alarm signal even when numerous stations are working, and also when there is atmospheric interference; 2. they must not be made to operate by "atmospherics" or by powerful signals other than the alarm signal; 3. they must possess a sensitivity equal to that of a crystal- detector receiver connected to the same antenna; 4. they must give warning when their operation ceases to be nor- mal. [til] (5) Before an automatic alarm receiver may be approved for use on ships, the administration having jurisdiction must be satis- fied by practical tests made under suitable conditions of interference, that the apparatus complies with the provisions of these Regulations. [ti2) (6) The adoption of the type of alarm signal mentioned in (1) shall not prevent an administration from authorizing the use of an automatic instrument complying with the conditions set forth above and which would be operated by the distress signal • • • - - - ••• J. URGENT SIGNAL [423] § 22. (1) In radiotelegraphy, the urgent signal shall consist of the group XXX transmitted three times, with the letters of each group, as well as the consecutive groups well separated; it shall be sent before the call. t 'fl1ent ~il(n.ll.