ITU-T Recommendations

Recommendation ITU-T Q.850 defines the format, encoding and semantics of cause in­formation elements/parameters and the usage of the location field, in the Digital Subscriber Signalling System No. 1 and the Signalling System No. 7 ISDN User Part. Many cause values are applicable to both DSS 1 and SS No. 7 ISUP and this Recommendation specifies the use of each cause value in other Recommendations.

Amendment 1 incorporates modifications that had been involuntarily omitted during the approval of revised Recommendation ITU-T Q.850 in 2018. Amendment 1 and Addendum 1, issued in 2001 and 2000 respectively, had not been incorporated in the final text of the Recommendation.

This amendment:

– Adds a reference to clause 2

– Adds case values to Table 1

– Adds clauses 6.2.7.1.10 bis and 6.2.7.1.18 bis