Each Attribute contained in a Module referenced by a Composite IOD defines a Type designation that indicates if a specific Attribute is required for all DIMSE operations/notifications associated with a SOP Class using this Module. PS 3.5 defines a choice of generic Type designations available for DICOM Attributes.
Note: The Type designation specified is generally determined by the value most appropriate for the C-STORE DIMSE Service.
The Type designation given in a Module is a default value and as such may be overridden by an IOD referencing the Module. Some Attributes may also be contained in more than one Module for the IOD. In that case, the Type designation applicable for the Attribute of the specific IOD is the lowest Type value (e.g. if type 2 is specified in one Module and type 3 in another, then type 2 shall apply), unless explicitly stated by the Attribute description.
The Type designation given in a Module (and/or IOD) may also be overridden by Service Class Definitions referencing the IOD containing the Module. PS 3.4 specifies the Service Class Definitions.
Modules referenced only by Normalized IODs do not contain Type designations. Modules referenced by both Normalized IODs and Composite IODs will contain a Type designation that only applies to Composite IODs and any specific conditions for Conditional Types (type 1C and 2C) also only apply to Composite IODs.