54 STAT.1 MULTILATERAL- TELECOMMUNICATION-, A PR. 8, 1938 1545 the duration of the interval between two dashes, one second. It can be transmitted by hand or by means of an automatic instrument. Any ship station working in the band of 365 to 515 kc (822 to 583 m), which is not provided with an automatic apparatus for the trans- mission of the auto-alarm signal, must be permanently equipped with a clock distinctly marking the seconds, preferably by means of a mov- ing hand completing one revolution per minute. This clock must be placed at a point sufficiently visible from the keying table so that the operator may, by watching it, easily and correctly time the dif- ferent elements of the alarm signal. [594] (2) The only purpose of this special signal is to set into oper- ation 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 warn- ing; in the latter case it can only be used by coast stations duly authorized by their government. [595] (3) In cases of distress, the use of the alarm signal is indicated in §5 (1) [No. 552]; in the case of urgent cyclone warnings, the emission Ante, p. 1536 . of this warning must begin only two minutes after the end of the alarm signal. [596] (4) The automatic instruments intended for the reception of the alarm signal must satisfy the following conditions: [597] 1. They must be set into operation by the alarm signal even when numerous stations are working, and also when there is atmos- pheric interference; [598] 2. They must not be made to operate by "atmospherics" or by powerful signals other than the alarm signal; [599] 3. They must possess a sensitivity equal to that of a crystal- detector receiver connected to the same antenna; [600] 4. They must give warning when their operation ceases to be normal. [601] (5) Before an automatic alarm receiver may be approved for use on ships, the administration having jurisdiction must be satisfied by practical tests made under suitable conditions of interference, that the apparatus complies with the provisions of these Regulations. [602] (6) The adoption of the type of alarm signal mentioned in (1) [No. 593] 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 [603] §22. (1) In radiotelegraphy, the urgent signal shall consist Urgent gnl. 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.
�
