Recommendation S.22

Replace by the following:

"CONVERSATION IMPOSSIBLE" AND OR PRE-RECORDED MESSAGE IN RESPONSE TO

J/BELL SIGNALS FROM A TELEX TERMINAL

(Geneva, 1980; amended at Melbourne, 1988)

The CCITT,

considering

(a)	that conventional telex terminals incorporate a facility that allows an operator at one end of an established connection to attract the attention of an operator at the other end, this being achieved by

transmitting J/BELL (combination No. 10 in International Telegraph Alphabet No. 2) in figure-case;

(b)	that technological developments and changing customer requirements have led to the introduction of the page-printing, receive-only, telex terminal, which, because of the absence of a keyboard, makes any conversational mode of operation impossible;

(c)	that this limitation is not indicated to a calling station at the time the connection is established and may well result in wasted circuit time through attempts to establish contact with the called station via the J/BELL facility;

(d)	that automatic calling and/or answering terminals employing data terminal equipment (DTE) and data circuit terminating equipment (DCE), in accordance with Recommendation S.16, are unlikely to have a conversational mode of operation;

(e)	that technological developments and changing operational requirements may lead to the retention of messages in storage until a suitable opportunity to print-out arises;

(f)	that it may be useful for called subscribers, who do not anticipate conversing with the calling subscriber, either because conversation is impossible or for any other reason, to answer by a pre-recorded message,

unanimously declares the following views

1.	Where a telex terminal is incapable of a conversational mode of operation, either through the absence of a keyboard or for local operational reasons, or if the subscriber wishes to deliver a pre-recorded message, then it is highly desirable, at least in new equipment, that such a terminal be able to automatically return an appropriate service signal sequence and/or the pre-recorded message on receipt of one or more ITA2 combination No. 10 characters (i.e. BELL signals) when preceded by ITA2 combination No. 30 (i.e. figure-shift).

2.	The recommended sequence of signals to be returned in such circumstances should incorporate the code expression.

CI Conversation Impossible

in conformity with the Recommendation cited in [1].

3.	The complete sequence incorporating the code expression CI should have a format that corresponds with the Recommendation cited in [2], concerning service signals for ineffective calls, except that it should not be followed by the clearing signal.

4.	Where a pre-recorded message is to be returned, then it should follow the rules established in the Note of this Recommendation, and should not be followed by the clearing signal.

If conversation is impossible after the pre-recorded message is delivered, this message should start with the CI conversation impossible sequence of signals as specified in §§ 2 and 3.

5.	As operators often key several repetitions of J/BELL (in figure-case) when attempting to contact a distant operator, a delay of 0.5 - 1.0 second should precede the transmission of the sequence described in §§ 2, 3 and 4 above, the delay to be measured from the stop element of the last J/BELL combination detected.

Note	- The length of the pre-recorded message should be unlimited provided that a pause of 1 sec. minimum is included within the message after every (x) characters, (the number of characters are to be decided).

- When conversation is impossible, the mandatory code expression CI should precede and follow the pre-recorded message.

- No "WRU" signals should be contained within the pre-recorded message up to the last code expression CI. Triggering of the calling party's answerback could be initiated after the end of the pre-recorded message.

- No combination 32 signals should be contained within the pre-recorded message.

The terminal and/or the network emitting the pre-recorded message should interrupt transmission immediately, when detecting modulation in the opposite direction.

Every pre-recorded message is not necessarily sent to the calling party upon simple reception of the triggering signal provided in § 1 above. Measures can be taken at the called party to reserve it to some special correspondents. The callers that are not qualified to receive it will then receive only the CI signal provided for in § 2."

REFERENCES

[1] CCITT Recommendation Operational provisions for the international telex service, Recommendation F.60, § 4.1.

[2] CCITT Recommendation Signalling conditions to be applied in the international telex service, Recommendation U.1, § 10.1.2.