ISO/IEC 15506:2003 PDF

Overview

ISO/IEC 15506:2003 defines the inter-exchange signalling protocol for the Message Waiting Indication (SS‑MWI) supplementary service at the Q reference point between Private Integrated services Network eXchanges (PINXs) in a Private Integrated Services Network (PISN). This Stage‑3 specification (part of the PSS1/QSIG family) describes how a Message Centre can activate, cancel or allow interrogation of message waiting indications for a Served User across interconnected PINXs.

Key topics and technical requirements

• Signalling scope: Protocol behaviour at the Q reference point for SS‑MWI between PINXs that form a PISN.
• Operations (ASN.1): SS‑MWI operations are defined in ASN.1 (e.g., mWIActivate, mWIDeactivate, mWIInterrogate) including argument/result structures and error conditions.
• Generic procedures: Reuses generic call‑independent supplementary service control procedures from ISO/IEC 11582 for originating, terminating and transit PINXs.
• State machine & timers: Defines SS‑MWI states for Message Centre and Served User PINXs and parameter values (timers T1, T2).
• Interworking rules: Additional signalling rules for interactions between SS‑MWI and other supplementary services and Additional Network Features (ANFs) - examples include Call Forwarding, Do Not Disturb, Call Transfer and Advice of Charge.
• Conformance: Includes a Protocol Implementation Conformance Statement (PICS) proforma (Annex A) and examples (Annex B).
• Interworking with public networks: Notes procedures for gateways to ISDNs and non‑ISDN networks where relevant.

Practical applications and who uses it

• PBX / PINX vendors: Implement SS‑MWI signalling across multi‑vendor enterprise networks to ensure a consistent Message Waiting indication (lamp, tone, display) across exchanges.
• System integrators / telecom architects: Design PISN interconnects and gateways that correctly propagate and interrogate MWI information.
• Interoperability and test labs: Use the PICS and ASN.1 definitions to validate conformance and interoperability of QSIG implementations.
• Service providers: Ensure reliable voicemail notification across private networks and proper interactions with other supplementary services.

Related standards

• ISO/IEC 11579‑1 - Q reference point and PINX configuration
• ISO/IEC 11582 - Generic functional protocol for supplementary services
• ISO/IEC 15505 - Stage‑1/2 service specification for SS‑MWI
• ETS 300 387 - Service specification method
• ITU‑T Q.950, X.208/X.209 - Supplementary service protocol structure and ASN.1 conventions

Keywords: ISO/IEC 15506, SS‑MWI, Message Waiting Indication, Q reference point, PINX, PISN, QSIG, ASN.1, signalling protocol, PICS, interoperability.