A Data Exchange Specification (DEX) - is a subset of the PLCS information model, designed to support data exchange for specific activities, providing guidance and rules for how to use and combine the selected entities and external Reference Data in that exchange.

Each DEX is defined within a given "context" where a "context" is a context in which a specialized vocabulary is employed. This may be an individual organization, a larger business community, or a particular project (or initiative). Each DEX is defined using the specialized vocabulary of its business context.