The structure and basic defi nitions of the branch format of technical documentation for signaling arrangement was considered in the given article. The branch format structure and its constituents were examined in detail. The examples of the contents of fi les, a detailed description of data types, as well as special attributes, such as transformation and stylization attributes were given. The description of a document’s reference frame was considered. The description of a document’s root element, its layers, sheets, as well as an embedded document’s image was given. In order to facilitate the comprehension of the structure’s description, some nuances were simplifi ed and not too extended. A full and basic description of technical documentation’s branch format may be obtained in offi cial technical documentation.