# Data structures overview

The DTM service includes the following data structures:

Structure | Description
--- | ---
DTM_BRI_TRUNK_STATUS | Stores the status and error statistics for BRI trunks.
DTM_TRUNK_STATE | Describes the current alarm and synchronization state of a trunk. This structure is included in the DTM_TRUNK_STATUS structure.
DTM_TRUNK_STATUS | Stores trunk information, alarms, trunk status, and error statistics.
DTM_START_PARMS | Determines the maximum number of events to send per second and when to send the events. This structure is referenced in the call to dtmStartTrunkMonitor.