Mandatory Modules
For each IOD, Mandatory Modules shall be supported per the definitions, semantics and requirements defined in Annex C in PS 3.3.
Conditional Modules
Conditional Modules are Mandatory Modules if specific conditions are met. If the specified conditions are not met, this Module shall not be supported; that is, no information defined in that Module shall be sent.
User Option Modules
User Option Modules may or may not be supported. If an optional Module is supported, the Attribute Types specified in the Modules in Annex C in PS 3.3 shall be supported.