The purpose of this document is to define the requirements of the OCR/VCS Standard interface and to convey these requirements in context to the reader. The interface specification is contained in the two appendices of this document, both of them normative: • System Design Description (SDD) This document specifies the class model, dynamic behaviour and exception handling of the interface. The API is included. • Interface Design Document (IDD) The IDD in Annex B defines the “payload” information for the interface. That is the data which is required for processing a mailpiece e.g. TIFF image format and XML data.