Overview
ISO/IEC 17311:2000 - Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Mapping functions for the employment of 64 kbit/s circuit mode connections with 8 kbit/s sub‑multiplexing - defines the mapping functions required to interconnect Private Integrated Services Network Exchanges (PINXs). The standard specifies a static mapping of a single 64 kbit/s circuit mode connection (D64U) to one 16 kbit/s signalling channel and six 8 kbit/s user channels at the Q reference point. It covers physical adaptation, channel mapping and bearer capabilities for inter‑PINX connections (IPC) using ITU‑T G.703 style interfaces.
Key topics and requirements
- Mapping functions (MP functional grouping)
- Static, fixed relationship between the C reference point (64 kbit/s IPC) and the Q reference point channels.
- Sub‑multiplexing of a 64 kbit/s circuit into: one 16 kbit/s D‑channel for inter‑PINX layer‑3 signalling and six 8 kbit/s U‑channels for user information.
- Physical adaptation (D64U)
- Layer‑1 termination compliant with ITU‑T Rec. G.703 for co‑directional 64 kbit/s interfaces.
- Bearer capabilities
- U‑channels: 8 kbit/s, supporting speech or unrestricted digital information. (Speech encoding itself is out of scope and handled by the Switching functional grouping.)
- D‑channel: 16 kbit/s, packet mode, unrestricted digital information for signalling.
- Conformance and testing
- Implementations must complete the Implementation Conformance Statement (ICS) proforma in Annex A.
- Scope limits
- Management functions for failure management and speech encoding algorithms are explicitly outside the scope.
Practical applications
- Interconnecting private PBX/PINX systems across leased 64 kbit/s links where bandwidth is sub‑multiplexed to carry signalling and multiple low‑rate user channels.
- Enabling inter‑PINX signalling (e.g., QSIG/DSS1 family protocols) and low‑rate data or compressed voice channels over a single D64U interface.
- Useful in legacy ISDN/PISN deployments, private enterprise networks, and carriers providing dedicated circuit services for enterprise telephony interconnect.
- Provides a standardized mapping for vendors, system integrators, test labs and procurement teams to ensure interoperability between PINX equipment.
Who should use this standard
- Telecom equipment manufacturers and PINX/PBX vendors implementing inter‑exchange mapping and physical interfaces.
- Network architects and system integrators designing private integrated services networks (PISN).
- Test laboratories, compliance engineers and procurement specialists verifying conformance to inter‑PINX signaling and channel mapping.
Related standards
- ISO/IEC 11579-1 (PINX reference configuration)
- ITU‑T Rec. G.703 (64 kbit/s physical/electrical interfaces)
- ITU‑T Rec. Q.920 / Q.921 (DSS1 data link layer)
- ITU‑T Rec. I.460 (multiplexing and rate adaptation)
- ECMA TR/76 (implementation guidance referenced)
Keywords: ISO/IEC 17311:2000, PINX, PISN, mapping functions, 64 kbit/s, 8 kbit/s sub‑multiplexing, D64U, G.703, Q reference point, inter‑PINX connection, ICS.