Specifies a common interface by which financial transaction card originated messages may be interchanged between acquirers and card issuers, message structure, format and content, data elements and values for data elements. Also specifies a numbering system for institution identification codes for financial institutions which do not have an ISO 7812 institution identification number and the procedures used for the registration of institution identification codes. Establishes procedures for a maintenance agency for codes used in this standard, the method of applying for codes and the method of obtaining lists of codes.