If, following the receipt of a SETUP message or during overlap sending, the network determines that the call information received from the user is invalid, (e.g. invalid number), then the network shall follow the procedures described in 5.3 with a cause such as one of the following:
No. 1 - Unassigned (unallocated) number;
No. 3 - No route to destination;
No. 22 - Number changed;
No. 28 - Invalid number format(incomplete number).