Page:United States Statutes at Large Volume 49 Part 2.djvu/519

 TELECOMMUNICATION CONVENTION. DECEMBER 9, 1932. ['-24] (2) In radiotelephony the urgent signal shall consist of three transmissions of the expression PAN (corresponding to the French pronunciation of the word "panne"); it shall be transmitted before the call. 1 [426] (3) The urgent signal shall indicate that the calling station has & very urgent message to transmit concerning the safety of a ship, an aircraft, or another vehicle, or concerning the safety of some person on board or sighted from on board. [426] (4) In particular, an aircraft sending a message to indicate that it is in trouble and on the point of being forced to land (or to take to the sea), but that it is not in need of immediate help, shall send the urgent signal before its message. ('127] (5) The urgent signal sent by an aircraft and not followed by a message shall mean that the aircraft is forced to land (or to take to the sea), is not able to transmit a message, but is not in need of immediate help. [428] (6) The urgent signal shall have priority over all other communications, except distress communications, and all mobile or land stations hearing it must take care not to interfere with the transmission of the message which follows the urgent signal. [429] (7) In case the urgent signal is used by a mobile station, this signal must, as & general rule, be addressed to a definite station. [430] § 23. When the urgent signal is used the messages which this signal precedes must, as a general rule, be written in plain language, except in the case of medical messages exchanged between ships or between a ship and a coast station. [431] § 24. (1) Mobile stations hearing the urgent signal must listen for at least 3 minutes. After this interval, and if no urgent message has been heard, they may resume their normal service. [432] (2) However, land and on-board stations which are in communication on waves other than that used for the transmission of the urgent signal and the call following it, may continue their normal work without interruption. [:33] § 25. (1) The urgent signal may be transmitted only with the authorization of the master or of the person responsible for the ship, aircraft, or any other vehicle carrying the mobile station. [434] (2) In the case of a land station, the urgent signal may he transmitted only with the approval of the responsible authority. K. SAFETY SIGNAL 2535 [436] § 26. (1) In radiotelegraphy, the safety signal shall consist folafety sigilal. of the group TTT, transmitted three times, with the letters of each group, as well as the consecutive groups, well separated. This signal I In the aeronautical service, at present, the signal PAN is also used as the radiotelegraph urgent signal; in this case the three letters must be well separated in order that the letters AN will not be changed into the letter P.