0x277D Universal Message Envelope (Interworking Only)

Network Protocol Data Intelligence. Also called “Interworking,” it is a software product that operates within Excel’s Call Control (Layer 4) and Services (Layer 5) call processing layers. NPDI is meant to enhance Excel’s call processing product offering by allowing call processing layers (specifically Layers 4 and 5) to perform advanced analysis, generation, and conversion of Network Signaling (NS) Layer 3 information.

Byte	Description
0, 1	Tag 0x277D
2, 3	Length Variable
4, 5	Value [0] Number of IEs
6, 7	Value [1] IE Type
8, 9	Value [2] IE Length
10, 11	Value [3] IE Data
:	:
:	Value [n] IE Type
:	Value [n] IE Length
:	Value [n] IE Data