CWA 14923-8:2004

This document describes the Sensors and Indicators Device Class ( SIU ) based on the basic architecture of J/XFS which is similar to the JavaPOS architecture. It is event driven
and asynchronous.
Three basic levels are defined in JavaPOS. For J/XFS this model is extended by a communication layer, which provides device communication that allows distribution of applications and devices within a network. So we have the following layers in J/XFS:
• Application
• Device Control and Manager
• Device Communication
• Device Service
Application developers program against control objects and the Device Manager which reside in the Device Control Layer. This is the usual interface between applications and J/XFS Devices. Device Control Objects access the Device Manager to find an associated Device Service. Device Service Objects provide the functionality to access the real device
(i.e. like a device driver).
During application startup the Device Manager is responsible for locating the desired Device Service Object and attaching this to the requesting Device Control Object. Location and/or routing information for the Device Manager reside in a central repository.
To support Sensors and Indicators Units, the basic Device Control structure is extended with various properties and methods specific to this device which are described on the following pages.