This standard defines the Information Retrieval Application Service (section 3) and specifies the Information Retrieval Application Protocol (section 4). The service definition describes services that support capabilities within an application; the services are in turn supported by the Z39.50 protocol. The description neither specifies nor constrains the implementation within a computer system. The protocol specification includes the definition of the protocol control information, the rules for exchanging this information, and the conformance requirements to be met by implementation of this protocol.

Intended for systems supporting information retrieval services, and for organizations such as information services, universities, libraries, and union catalogue centers, this standard addresses connection-oriented, program-to-program communication. It does not address interchange of information with terminals or via other physical media.