DICOM Transfer Syntax Negotiation
Transfer Syntax Negotiation in DICOM is relatively simple, but often misunderstood. It is important to understand this fully before attempting to take control using DicomObjects.
The transfer syntaxes available for network transmission depend on what is agreed between the applications during initial negotiation (and at no other time. The steps are as follows:
The SCU sends the SCP a list of “presentation contexts”, each of which has a SOP class and one or more transfer syntaxes.
Network Transfer Syntax Control (NET)
Background in earlier versions of DicomObjects, both .NET & COM the same basic mechanism was used for selecting transfer syntaxes:
When initiating, they can be created specifically using Contexts.Add etc. When accepting, they can be selected specifically using Context.AcceptedTS or Reject If neither of the above is used (as most people don’t) then a default mechansim is used, based on the TransferSyntax registry hive, which allows: Setting of specific values for different SOP classes using TransferSyntax/SOP class UID A more generic setting for all other SOP classes in the TransferSyntax/ default value This system, which is described here worked well for many years, but has 3 main drawbacks: