| 摘要 |
The CCIR,
CONSIDERING
(a) that telephone circuit operation is substantially improved by the use of semi-automatic instead of manual working;
(b) that HF radiotelephone circuits will continue to be used for many years to come in the international fixed service;
(c) that employment of CCITT signalling codes on such circuits, even when they are equipped with systems of the type described in Recommendation 455, is difficult owing to the loss probabilities prescribed for the use of these codes in the international service;
(d) that, on the other hand, the use of signalling methods specially intended for radiotelephone channels makes it possible to transmit the information required for remote connection of an operator in one country to an automatic exchange in another country;
(e) that the FSK signalling system now in use on HF radiotelegraph circuits meets the requirements of (d) above;
(f) that Report 434 contains precise details on the use of, and tests made by certain countries with devices using the signals mentioned in (e) above and that the results are very satisfactory |
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