Description: The Annunciator table is used to control the set of annunciators associated with a resource. An Annunciator management instrument holds a set of individual announcements. The function of the Annunciator is to communicate the contents of its current set via whatever platform-specific mechanism is associated with that particular Annunciator management instrument. For example, if announcements are to be communicated via lighting a set of LEDs on a front-panel display, the Annunciator management instrument may analyze its current set of announcements and turn on a single LED reflecting the most severe condition found, or turn on a 'System Ok' LED if there are currently no items in the set. A different Annunciator may continuously scroll each announcement in its set on a text display, as well as turning on LEDs and setting dry-contact relays to reflect the severity of conditions present. A third Annunciator may announce items in its set by sending messages to a proprietary management system, or by sending emails or pages to a system technician.

The Annunciator provides a common interface to these varied mechanisms for announcing conditions, so the HPI User is not burdened by platform-to-platform differences. However, the current content of any annunciator management instrument is not defined by the HPI standard in the same way that the contents of the DAT are defined. Thus, the HPI implementation and HPI Users can exert more control over what conditions should be announced. Further, a platform can contain multiple Annunciator management instruments, each reflecting a different physical announcement device in the platform. By exposing each separately, HPI Users and the HPI implementation can control which conditions are handled by each announcement device. An Annunciator management instrument may be implemented using other HPI controls that are in 'auto' mode; for example, digital controls to turn LEDs on and off, stream controls to sound audible alerts, and/or text controls to display detailed information. However, A nnunciators may also operate directly to report conditions using mechanisms that are not themselves visible directly in the HPI interface.

Over time, announcements are added to and deleted from an Annunciator`s current set of announcements. This may be done automatically by the HPI implementation to reflect platform fault conditions, or by the HPI User via the HPI interface. When announcements are added or deleted automatically by the HPI implementation, it is implementation-specific which announcements are added or removed.