ITU-T U 4-1988 EXCHANGE OF INFORMATION REGARDING SIGNALS DESTINED TO BE USED OVER INTERNATIONAL CIRCUITS CONCERNED WITH SWITCHED TELEPRINTER NETWORKS《无效呼叫尝试或信号故障时连接到用户电报网的自动终端的反应》.pdf

1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 5 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%2!0(G0G037)4#().%.%2!,%8#(!.%G0G0/modified at New Delhi, 1960 and Geneva, 1972)The CCITT,considering(a) that certain signals and certain characteristics of signals used in the international telex service

2、have beenstandardized in Recommendation U.1;(b) that certain Administrations have introduced automatic telex transit switching facilities based upon thesignalling standards shown in Recommendation U.1;(c) that standardized signals for the European switched network for the public telegram service (ge

3、ntexnetwork) are advocated in Recommendation U.30;(d) that in view of the foregoing an exchange of information regarding the precise nature of the signalsproposed to be used in the above-mentioned services by interested Administrations would be very useful;(e) that certain Administrations have alrea

4、dy supplied such details regarding their telex services in a usefulform (see supplements to the documents of the VIIIth Plenary Assembly of the CCIT, and subsequent PlenaryAssemblies of the CCITT),unanimously recommendsthat Administrations concerned in the international telex service and gentex netw

5、ork be invited to supply to theCCITT time-sequence diagrams showing in each case the signals at present transmitted or proposed to be transmittedover the international circuit for incoming calls. The diagrams should show not only the sequence and characteristics ofthe signals, but also the timing tolerances to be expected. The diagrams should show the signalling conditionsapplicable to transit as well as to terminal calls, including any conversion of the signals that are received from thedestination network.