ITU-T U 43-1988 FOLLOW-ON CALLS《随后呼叫》.pdf

1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 5 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%2!0(G0G037)4#().0!24)#5,!2G0G03).!,).G0G0 amended at Melbourne, 1988)The CCITT,consideringthat users of the telex service often have several messages ready to transmit at the same time to differentsubscri

2、bers and that it would therefore be an advantage for them to be able to transmit these messages one after theother, keeping the part of the communication chain already established in a seized condition and having the calls set upsuccessively, without having to go through the whole procedure of setti

3、ng up a new call for each message,unanimously recommends1 that Administrations should be able to offer the possibility of follow-on calls to their subscribers;2 that the procedure and control of such calls are the responsibility of the originating country;3 that if the originating country is not abl

4、e to provide this facility to their subscribers, the terminating countryonly could perform the follow-on function taking into account the following restrictions:3.1 that the Administration of the terminating country offering the possibility of follow-on calls shall take all thenecessary steps to pro

5、hibit the use of this arrangement for setting up calls in transit to a third country;3.2 that the chargeable duration for the caller shall be the whole time from the moment when the first call is set upto the moment when the last one is terminated, the duration of the intermediate dialling being inc

6、luded in thechargeable duration;4 that if the alternative in 3 is offered, the procedure should be as follows:4.1 the caller in the originating country wishing to make a new call to a subscriber in the terminating country shallindicate his wish to do so by sending a signal consisting of a special se

7、quence made up of four combinations No. 12(LLLL); usage of a fifth or more Ls is a national matter. This combination should be recognized in letter shift modeonly;4.2 the terminating international exchange must be able to detect the signal, to which it shall reply by sending theproceed to select seq

8、uence (e.g. GA), inviting the caller to indicate the new number to be called;4.3 the caller shall transmit the new number to be called, and the call shall then be set up in the terminating countryin accordance with the usual procedure;4.4 the originating network shall ignore this new dialling and shall simply keep the connection seized as if the firstcall were being continued.