Page:United States Statutes at Large Volume 45 Part 2.djvu/1182

 2858 INTERNATIONAL RADIO CONVENTION. NOVEMBER 25,1927. oJIoTarmstroBot (talk)pro. (6) In principle, a radiotelegram containing more than 100 words . shall be considered as forming a series, or shall terminate a series then under way. (7) As a general rule, long radiotelegrams in plain language, code, or cipher, shall be transmitted in sections, each section containing 50 words in the case of plain language and 20 words or groups where code or cipher is used. (8) At the end of each section the signal •• __ •• (?) meaning: "Have you received the radiotelegram correctly up to this point,?'~ shall be transmitted. If the section has been correctly received, the receiving station shall send the letter K and the transmission of the radiotelegram shall be continued. 9 (a) The transmission of a radiotelegram shall be terminated by the signal • _. _. (end of transmission) followed by the call signal of the sending station and the letter K. (b) In case of transmission in series, the call signal of the sending station and the letter K shall be sent only at the end of the series. 10 (a) Acknowledgment of receipt of a radio telegram shall be sent by means of the letter R followed by the number of the radiotele- gram; this acknowledgment of receipt shall be preceded by the fol- lowing formula: call signal of the sending station, word DE, call signal of the receiving station. (b) Acknowledgment of receipt of a series of radiotelegrams shall be sent by means of the letter R followed by the number of radiotele- grams received as well as by the numbers of the first and of the last telegram composing the series. This acknowledgment of receipt shall be preceded by the formula given above. . (11) The concluslOn of work between two stations shall be indicated by each of them, by m.eans of the signal ••• _ • _ (end of work) followed by its own call signal. §4. (1) If the calling station intends to transmit its traffic with a type of wave and/or on a frequency other than those employed for the call, it shall send after its own call signal the service indications defining the type of wave and/or the frequency which it proposes to use for its transmission. The absence of these service indications shall signify that it does not intend to change the type of wave or frequency. (2) If the station called wishes the calling station to send on a type of wave and/or frequency other than those used for the call, it shall add to the reply formula service indications defining the type of wave and/or the frequency which it desires to be used. The absence of these service indications shall signify that it does not desire that the type of wave and/or the frequency used for the call be chaIngedh' allin . h.ditedh .. . (3)ftec gstation asm ca t atItISgomgtousefor transmission a type of wave and/or a frequency other than those with which the call was made, the station called in the reply formula shall precede the letter K by abbreviations, indicating thttt from then on It will listen on the type of wave and/or the frequency announced and that it itself, will use the said type of wave and/or frequency for the entire period of communication. (4) If the calling station is a land station which, according to the provisions of the present regulations, may employ a wave other than those which it is possible for the mobile station to transmit, it may after having established contact, use this wave to transmit its traffic. In such case the procedure shall be as follows: (a) The land station shall call the mobile station by using the wave on which the latter is keeping watch; and after having obtained an answer shall inform it by means of the appropriate abbrevia.tion that it must listen thereafter on the wave which it intends to use.

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