This International Standard defines the requirements for the handling of network addresses for the identification of entities which use or provide telecommunication services offered by Private Integrated Services Networks (PISNs). This International Standard covers numbering, including the requirements for the support of a Private Numbering Plan, the addressing of network service access points for open systems interconnection (OSI NSAP addressing), and the support of subaddressing.

This International Standard is applicable to Private Integrated Services Network Exchanges with broad-band and narrow-band capabilities (PINX) and to terminals to be attached to the access of PINXs. Any use by a PINX of the Support of Private Numbering Plans supplementary service provided by a public ISDN is outside the scope of this International Standard.

Although this International Standard does not explicitly describe its application to location-independent (mobile) addressable entities, this application is not precluded.