PS3.4 of the DICOM Standard defines a number of Service Classes. A Service Class associates one or more Information Objects with one or more Commands to be performed upon these objects. Service Class Specifications state requirements for Command Elements and how resulting Commands are applied to Information Objects. Service Class Specifications state requirements for both providers and users of communications services.

PS3.4 of the DICOM Standard defines the characteristics shared by all Service Classes, and how a Conformance Statement to an individual Service Class is structured. It contains a number of normative annexes that describe individual Service Classes in detail.

Examples of Service Classes include the following:

PS3.4 defines the operations performed upon the Information Objects defined in PS3.3. PS3.7 defines the Commands and protocols for using the Commands to accomplish the operations and notifications described in PS3.4.