This technical specification specifies the framework for the specification of Component Interface Specifications (CIS) for Energy Management System Application Program Interfaces (EMS-API). A CIS specifies the interfaces that a component (or application) should implement to be able to exchange information with other components (or applications) and/or to access publicly available data in a standard way. IEC 61970-1 provides the EMS-API reference model upon which this standard is based. In that Reference model, the terminology used in this technical specification is introduced and the role of the CIS is explained. This part of IEC 61970 specifically provides a framework for the specification of the Level 1 Functional Requirements documents. It explains the separation of these specifications into two major groups. One group of standards defines the generic services that a component can use for exchanging information with another component or for accessing public data. The other group defines the information content of messages that a component or system exchanges with other components. IEC 61970-401 also provides an overview of the functionality included in the CIS standards. This functionality is described as a set of generic services using narrative text and Unified Modeling Language (UML) notation. These generic services can be used by any application to either (1) exchange information with another independently developed application/system or (2) for public data access. The generic services specify the specific events, methods, and properties that can be used by applications for this purpose. This part of IEC 61970 also provides a roadmap to explain the contents of each of the specifications in the future IEC 61970-4XX series and the underlying industry de facto standards that are incorporated. A separate series of documents (i.e., the future IEC 61970-5XX) describe mappings to specific technologies for the implementation of the future IEC 61970-4XX standards. To ensure interoperability, there should be a standard mapping for each interface to each technology. For example, if Java is the chosen implementation technology, then there needs to be a standard mapping of the publish/subscribe services specified in the CIS document to Java services.