This specification describes the functionality of the services provided by Alarms (ALM) under XFS, by defining the service-specific commands that can be issued, using the WFSGetInfo, WFSAsyncGetInfo, WFSExecute and WFSAsyncExecute functions. This section describes the functionality of an Alarm (ALM) service that applies to both attended and unattended (self-service) devices.
The Alarm device class is provided as a separate service due to the need to set or reset an Alarm when one or more logical services associated with an attended CDM or unattended (self-service) device are locked. Because logical services can be locked by the application the Alarm is implemented in a separate device class to ensure that a set (trigger) or reset operation can be performed at any time.

XFS 3.40 has been designed to minimize backwards compatibility issues. This document highlights the changes made to the Alarm (ALM) Specification device class between version 3.30 and 3.40, by highlighting the additions and deletions to the text.