# IMGT data structures

The IMGT service uses data structures to configure the ISDN protocol stack, send messages to the protocol stack, and receive messages from the protocol stack. This section presents the IMGT data structures in detail.

Structures and definitions directly related to functions are defined in the imgtdef.h header file. Structures and definitions related to primitive codes are defined in the imgtsvc.h header file.

## Messaging structures

Messaging structures are used to convey messages and message data between the ISDN protocol stack and the application:

- IMGT_MESSAGE structure

- IMGT_MSG_PACKET structure

- IMGT_CONFIG structure

For more information on sending and receiving IMGT messages, refer to the IMGT application overview.

## Primitive-related structures

The primitive-related structures section describes the primitives that can be sent in an IMGT message and the structures associated with these primitives. The tables in this section list those fields that are implemented for each variant.

The primitive-related structures include:

- IMGT_B_CHANNEL_STATUS_CO

- IMGT_B_CHANNEL_STATUS_RQ

- IMGT_D_CHANNEL_EST_CO

- IMGT_D_CHANNEL_EST_RQ

- IMGT_D_CHANNEL_REL_CO

- IMGT_D_CHANNEL_REL_RQ

- IMGT_D_CHANNEL_STATUS_CO

- IMGT_D_CHANNEL_STATUS_IN

- IMGT_D_CHANNEL_STATUS_RQ

- IMGT_REPORT_IN

- IMGT_RESTART_IN

- IMGT_SERVICE_CO

- IMGT_SERVICE_IN

- IMGT_SERVICE_RQ