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- Recommendation U.70
- TELEX SERVICE SIGNALS FOR
- TELEX TO TELETEX INTERWORKING
- (Malaga-Torremolinos, 1984)
- The CCITT,
- considering
- (a) that a basic interworking on international connections will be at 50
- bauds using an international telex network and that any telex subscriber can call
- conversion facilities in various countries;
- (b) that Recommendation F.201 specifies:
- - that a validation of a called Teletex terminal is mandatory. The
- validation is performed either by a direct validation call or by a data
- base access;
- - that if a message delivery to a Teletex terminal fails in the case of
- interworking with two-stage selection procedure, the conversion
- facility should send a non-delivery notification to a telex terminal;
- (c) that Recommendation S.90 specifies Teletex requirements for
- interworking with the telex service and Recommendations S.62 and S.70 specify
- control procedures and a network-independent basic transport service for a
- Teletex;
- (d) that Recommendation X.96 specifies call progress signals in a public
- data network,
- unanimously declares the following view
- 1 Scope
- This Recommendation defines service signals which are to be sent back to
- the telex terminal in the event of unsuccessful validation for called Teletex
- terminal addresses, and service signals of the last delivery attempt to the
- Teletex terminal which are to be sent to the telex terminal as a part of
- non-delivery notification.
- TABLE 1/U.70
-
- MONTAGE: REPRENDRE ORIGINAUX DU LIVRE ROUGE.
- PAS DE NOUVELLE SAISIE = MAINTENU LIVRE ROUGE
- 2 Principles
- The following principles should be taken into consideration:
- 2.1 Call progress signals arriving from the Teletex network will be converted
- without changing their original meaning as far as possible.
- 2.2 A faulty condition between the Teletex network and the conversion facility
- will be regarded as a faulty condition within the network.
- 2.3 A faulty condition between the Teletex network and the Teletex terminal
- will be regarded as a fault of the terminal.
- 3 Telex service signals
- 1n general, telex service signals specified in Recommendation F.60 should
- be used. However, the telex service signals listed below will be used in the
- following circumstances:
- 3.1 1f the format of the Teletex address part is incorrect, the service signal
- NP will be returned.
- 3.2 1f the direct validation call is unsuccessful, the conversion facility
- will transmit the service signals specified in Table 1/U.70 to the telex
- terminal.
- 3.3 If the validation by data base access is unsuccessful, the conversion
- facility will transmit the service signals specified in Table 2/U.70.
- 3.4 If the message delivery to the Teletex terminal is unsuccessful, the
- conversion facility will transmit the service signals of the last delivery
- attempt which are specified in Table 1/U.70, as a part of non-delivery
- notification to the telex terminal.
- TABLE 2/U.70
- Service signals for unsuccessful validation by data base access
- Abnormal conditions Service signal
- Unsuccessful results NP
- Note - In addition to the case "the number does not exist",
- other cases, for example, "the number is being temporarily
- prohibited" or "the number is out of order", might be
- considered as abnormal conditions. But at this moment such
- conditions and the service signals corresponding to them are
- for further study.
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- Fascicle VII.2 - Rec. U.70 PAGE1
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- PAGE2 Fascicle VII.2 - Rec. U.70
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