Recommendation U.43

FOLLOW-ON CALLS

(Malaga-Torremolinos, 1984; amended at Melbourne, 1988)

The CCITT,

considering

that users of the telex service often have several messages ready to transmit at the same time to different subscribers and that it would therefore be an advantage for them to be able to transmit these messages one after the other, keeping the part of the communication chain already established in a seized condition and having the calls set up successively, without having to go through the whole procedure of setting up a new call for each message,

unanimously recommends

1	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 able to provide this facility to their subscribers, the terminating country only 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 the necessary steps to prohibit 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 up to the moment when the last one is terminated, the duration of the intermediate dialling being included in the chargeable duration;

4	that if the alternative in S 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 shall indicate his wish to do so by sending a signal consisting of a special sequence 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 mode only;

4.2	the terminating international exchange must be able to detect the signal, to which it shall reply by sending the proceed to select sequence (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 country in 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 first call were being continued.