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. NOTE - Previous Amendment(s) to Q.1902.4 (07/2001) still apply and need to be taken into account when applying this Amendment.