CONTENTS

�Introduction���� � iv
�1���� Methods of validation
�2���� Full validation procedures
������� 2.1���� Validation information flow
������� 2.2���� Authorization request
������� 2.3���� Request response
������� 2.4���� Call disposition (optional)
�3���� Limited validation procedures
������� 3.1���� Types of limited validation procedures
������� 3.2���� Location of personal identifying information
Annex� A� �� Security during validation over an X.25 network
������� A.2���� Recommendations
������� A.3���� Validation security procedures