This part of ISO/IEC 13066 defines the responsibilities of different information technology (IT) and assistive technology (AT) functional units in supporting interoperability. It recognizes that AT can be provided both as functional units that are installed or otherwise connected to a system or can be utilized by being provided as a service which is accessed via communications connections. It bases these responsibilities on fundamental IT definitions of major types of functional units. It focuses on the utilization of standard, public interfaces for functional units and on the provision of accessible documentation of their capabilities.This part of ISO/IEC1