# Overview of Q.931 data

NMS ISDN allows an application to include raw Q.931 data in one or more completely custom-built information elements (IEs) in messages sent to the stack. These information elements, called transparent IEs, are inserted verbatim in the Q.931 message generated by the stack. This specification method allows an application access to IEs and fields in IEs that cannot be accessed using the macros associated with ACU messages. This method can be used to specify both standard IEs (codeset 0) and extensions (such as codeset 6 and 7).

An application can also access and read the raw data in an incoming Q.931 message, rather than reading returned values for specific fields in data structures.