This ETS specifies the Integrated Services Digital Network Programming Communication Interface (ISDN PCI) for the accessing and administering of the following ISDN services: - Bearer Services (as defined in ETS 300 102-1 [2]); - Supplementary Services (as defined in ETS 300 196); - Virtual Circuit (VC) or Permanent Virtual Circuit (PVC) Bearer Services on the B- and D-channels. The PCI defined in this ETS: - covers both Basic and Primary rate ISDN access; - is independent of operating system@ hardware and programming languages. It provides language and operating system binding for common operating system environments; - supports concurrent applications; - supports concurrent protocol stacks related to data exchange; - supports application access to multiple channels on multiple ISDN accesses; - provides the Open Systems Interconnection (OSI) connection-mode network service as defined by CCITT Recommendation X.213 [7] using the method defined in ISO 9574; - provides an interface for applications requiring direct control of ISDN services; - shows the impact of security issues on the interface; - has been defined to allow future extension of functionality.