џWPCL ћџ2BJ|xа АH аа АА X агга ХА6p&А6p&Х аеЄ† а Hр аааУ Уб cмˆ4 PŽТ б Fascicle VII.2 Р-Р Rec. U.21 PAGE1 Єее† а HH аааУ Уб cмˆ4 PŽТ бPAGE1 Fascicle VII.2 Р-Р Rec. U.21 еа HH ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаа X  аУ Уб cмˆ4 PŽТ бRecommendation U.21 аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр8?Сб cмˆ4 PŽТ бOPERATOR RECALL ON A TELEX CALL SET UP Ср8EСON A RADIOTELEGRAPH CIRCUIT аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр8=Сб cмˆ4 PŽТ бФ ФУУ(New Delhi, 1960; amended at Geneva, 1964)ФФ аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHјP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТа ТThe CCITT,ЦЦ аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаУУconsidering а H№ ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаФФС  С(a)СјСthat experience has shown that, for telex calls set up over a radiotelegraph circuitй9€ telex calls set up over a radiotelegraph circuit9йб cмˆ4 PŽТ б, it was useful to enable the telex subscriber to cause an operator to reР-Рenter on a call in progress without interrupting it; С  С(b)СјСthat such reР-Рentry may be of interest in the following cases as well as in the case of a defective connection: а H ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТа ТТ№ ТС€ Сб cмˆ4 PŽТ бi)СpСWhen a subscriber decides, in the course of a call, to change from a plain text to a cypher he can call the operators in the terminal radio exchanges and ask them to interrupt the delay signal, which might otherwise disturb the synchronism between the cyphering apparatus used at the two ends.ЦЦ а H аТа ТТ№ ТС€ Сii)СpСWhen a subscriber has sent a message but waits a very long time for a reply from his correspondent, he can ask the operator whether his message is still being stored or whether it is expected that any interruption to the radio circuit will continue. If need be, he can then choose another means of communication (telegram or telephone call) to send an urgent message to its destination;ЦЦ а H аС С(c)СpСthat although it seems that reР-Рentry by an operator will be limited mainly to national networks (for example by a subscriber calling the controlling telex operator on the radiotelegraph circuit), international standardization of anУУ operator recallФФ signal would be useful if the controlling telex operator on the radiotelegraph circuit is located in a transit country, and also for intermediate manual switches; this would no doubt prove to be a great advantage when this possibility is generally utilized, УУunanimously declares the following view а H аФФС С(1)СpСIf the Administrations concerned agree on the use of a special signal enabling a subscriber to recall an international telex operator's position making use of radiotelegraph circuits, such a recall must not cause release of a call in progress. С С(2)СpСThisб cмˆ4 PŽТ б operator recall signal will consist of the following sequence: combinations No. 28 (lineР-Рfeed) followed by four combinations No. 27 (carriageР-Рreturn). С С(3)СpСThe detection device causing reР-Рentry by the operator will be controlled by the receipt of four consecutive combinations No. 27; combinations No. 28 will only be used to avoid superposition of the text on the receiving teleprinter and will not have to be recognized by the detection device. С С(4)СpСThe equipment for discriminating the operator recall signal will be switched off by a sequence of four consecutive combinations No. 19 (signal for transfer to data). ‚У Уб cмˆ4 PŽТ б