This document defines a file format for the generation of postal address directories. It is designed to hold all information necessary to support address reading software including data required for forwarding applications. In typical postal automation systems these files will be processed by directory generation software which creates application specific loadable data. This data - usually referred to as operational directory - is heavily compressed and contains access tables tailored for the specific reading software. Not in the scope of this document are topics external to file like compression, checksums, the interface for transmission to the supplier, modification permissions, error handling on inconsistent data and undo in updates.