This part of ISO/IEC 15944 provides a set of UML class diagrams and conceptual explanations that circumscribe the Open-edi Business Transaction Ontology. It explains the mechanics of a business transaction state machine — the procedural component of an OeBTO — and the (internal) constraint component of OeBTO — its repository for business rules. This part of ISO/IEC 15944 addresses collaborations among independent trading partners as defined in ISO/IEC 15944-1. This part of ISO/IEC 15944 applies to both binary collaborations (buyer and seller) and mediated collaborations (buyer, seller, third-party). The ontological features described herein propose standards only for the BOV — that is, the business aspects of business transactions as they are defined in ISO/IEC 15944-1.