ISO/IEC 15431:2003 PDF

Overview

ISO/IEC 15431:2003 specifies the signalling protocol for Wireless Terminal Call Handling additional network features at the Q reference point between Private Integrated services Network eXchanges (PINX) within a Private Integrated Services Network (PISN). It provides the stage‑3 protocol (QSIG/PSS1) details to support ANF‑WTMI (incoming call routing to a wireless terminal within the PISN) and ANF‑WTMO (processing outgoing calls from a wireless terminal at its home location). The standard operates on top of basic circuit‑switched call control and defines coding, messages, states and timer behaviour for inter‑exchange signalling in enterprise telephony environments. Roaming outside the PISN is explicitly out of scope.

Key topics and requirements

• Scope and conformance
  • Applies to PINXs that interconnect to form a PISN; conformance verified via the PICS proforma.
• Primary features
  • ANF‑WTMI: directs incoming calls to a WTMI user anywhere within the PISN when location is known.
  • ANF‑WTMO: allows originating PINX to have call requests processed at the user’s home PINX.
• Protocol elements
  • Message formats, ASN.1 definitions and APDU usage for Q reference point signalling.
  • State machines for Rerouteing, WTMI‑detect, Home, Visitor, Originating and Transit PINXs.
  • Timers (e.g., T1, T2) and operational timer requirements.
• Interaction handling
  • Detailed protocol interactions with many supplementary services and ANFs (call forwarding, call transfer, Do Not Disturb, Message Waiting Indication, WT location/INFO, authentication, etc.).
• Supporting material
  • Annexes with PICS proforma, ASN.1 imports, message sequence examples and SDL procedure descriptions for implementation and testing.

Applications and users

ISO/IEC 15431:2003 is primarily useful for:

• PINX/PBX vendors implementing QSIG features for enterprise telephony and wireless terminal mobility.
• Network and protocol engineers designing inter‑exchange signalling between private exchanges.
• System integrators delivering PISN deployments requiring WT mobility and call handling across multiple PINXs.
• Conformance and test labs validating interoperability using the provided PICS, ASN.1, and message examples.
• Enterprise IT architects planning private network features for unified communications with wireless terminal support.

Keywords: ISO/IEC 15431:2003, Q reference point, PISN, PINX, ANF‑WTMI, ANF‑WTMO, QSIG, wireless terminal call handling, inter‑exchange signalling.

Related standards

• ISO/IEC 15430 (stage 1/2 service model for Wireless Terminal Call Handling)
• ISO/IEC 11572 (basic circuit‑switched call control)
• ISO/IEC 11582 (generic supplementary‑service procedures)
• ISO/IEC 11579‑1 (PISN reference configuration) and other QSIG-related standards for supplementary services

This standard is essential for interoperable wireless terminal mobility features in private integrated services networks and for implementing robust QSIG signalling between enterprise exchanges.