ISO/IEC 13865:2003 PDF

Overview

ISO/IEC 13865:2003 - "Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Call Transfer supplementary service (SS-CT)" - defines the Call Transfer supplementary service for Private Integrated Services Networks (PISNs). The standard contains the Stage 1 (user-level) and Stage 2 (functional model and information flows) specifications for SS-CT and gives two network operation methods: transfer by join and transfer by rerouteing. It is intended as the normative foundation for later Stage 3 signalling and protocol specifications.

Key topics and technical requirements

• Service semantics (Stage 1):
  • SS-CT allows a served user (User A) to transform two of their calls into a direct call between the other parties (User B and User C). At least one of the two calls must be answered.
  • Both calls may be incoming or outgoing; the standard assumes both calls are already established when transfer is requested.
  • The transfer result is a new B–C call; original connections to A are released.
• Operational constraints:
  • Transfer only accepted when valid call identities and compatibility conditions are met.
  • Bearer capability compatibility rules are specified (e.g., same bearer capability, or Speech vs. 3.1 kHz audio interworking).
  • Network must prevent illegal connections (e.g., Closed User Group restrictions).
  • Support for subaddress exchange and presentation/restriction interactions (CLI/COLP/CNIP etc.) is addressed.
• Functional model and information flows (Stage 2):
  • Identifies functional entities (FEs) and inter‑FE relationships required to effect transfer.
  • Provides information flow definitions and examples for transfer by join and transfer by rerouteing.
• Conformance note:
  • To claim conformance, a Stage 3 specification (signalling protocols and equipment behaviour) must support the Stage 1 and Stage 2 aspects applicable to the interface/equipment.

Applications and who uses it

• Telecom equipment vendors and firmware developers implementing PISN/PINX features.
• Standards engineers producing Stage 3 signalling protocols that enable call transfer in private networks.
• Network architects and PISN operators who need to ensure feature compatibility, lawful restrictions (CUG), and correct functional allocation.
• System integrators and VoIP gateway vendors working on interworking between ISDN and non‑ISDN endpoints where call transfer semantics must be preserved.

Related standards

• ISO/IEC 11574 - Basic call services for PISN
• ISO/IEC 11579-1 - PINX reference configuration
• ETS 300 387 - Method for specification of basic and supplementary services
• ISO/IEC 13864, ISO/IEC 14136 - Related identification/name supplementary service standards
• ITU‑T Recs I.112, I.210 and Z.100 - Vocabulary, service principles and SDL

Keywords: ISO/IEC 13865:2003, SS-CT, Call Transfer supplementary service, PISN, PINX, transfer by join, transfer by rerouteing, functional model, information flows, ISO/IEC 11574.