Page:United States Statutes at Large Volume 49 Part 2.djvu/505

TELECOMMUNICATION CONVENTION. DECEMBER 9, 1932. (b) In radiotelegraphy on continuous waves for aircraft of which the crew includes a radiotelegraph operator. Calling: type-A2 waves. Working: type-AI waves (type A2 shall be permitted in the case of work on short waves). [358] 2. For aeronautical stations: (a) In radiotelephony (calling and working) when the station must communicate with an aircraft of which the crew does not include a radiotelegraph operator. (b) In radiotelegraphy, when the station must commu- nicate with an aircraft of which the crew includes a radiotelegraph operator. Type-AI waves (calling and working). Type-A2 waves shall be permitted (calling and work- ing) in the case of short waves. ARTICLE 20 Interference 2521 [3611] § 1. (1) The exchange of unnecessary signals or messages Interreren~. shall be forbidden to all stations. rOO] (2) Tests and experiments shall be permitted in mobile stations if they do not interfere with the service of other stations. As for stations other than mobile stations, each administration shall judge, before authorizing them, whether or not the proposed tests or experiments are likely to interfere with the service of other stations. [881] § 2. It is recommended that traffic relating to public corre- spondence be transmitted on type-AI waves rather than on type-A2 waves, and on type-A2 waves rather than on type-B waves. [362) § 3. All stations of the mobile service shall be required to ex- change traffic with the minimum of radiated power necessary to insure good communication. rea) § 4. Except in cases of distress, communications between on- board stations must not interfere with the work of land stations. When this work is thus interfered with, the on-board stations which cause it must stop transmitting or change wave, upon the first request of the land station concerned. [3M) § 5. Test and adjustment signals must be selected in such a way that there will result no confusion with a signal, an abbreviation, etc., having a particular meaning defined by these Regulations or by the International Code of Signals. [366) § 6. (1) When it is necessary to transmit test or adjustment signals, and there is danger of interfering with the service of the ad- joining land station, permission must be obtained from that land station before such transmissions are made. [386] (2) Any station making transmissions for purposes of testing, adjusting, or experimenting, must transmit its call signal or,