This amendment to the ISUP Specification ITU-T Rec. Q.1902.4 (07/2001) contains seven modifications:

1)          Correction of a cut and paste error in 7.4.1 and 7.4.4;

2)          Modifications of the codec negotiation in 8.3;

3)          Fallback procedures modification of 8.6.2.2.2;

4)          Signalling procedures for automatic rerouting (crankback); new procedures in a new clause 8.21;

5)          Procedures to support the calling party's category for calls from mobile terminals; new procedures in a new clause 8.22;

6)          Handling of national use elements at an international gateway SN or CMN; new procedures in a new clause 13.8;

7)          Two message flows examples in codec negotiation and modification in Appendix I.