IEC 60728-7-3:2009

Overview - IEC 60728-7-3:2009 (PSTIB) for HFC OSP power monitoring

IEC 60728-7-3:2009 specifies the Power Supply to Transponder Interface Bus (PSTIB) for Hybrid Fibre Coax (HFC) Outside Plant (OSP) power supplies. The standard defines the physical (PHY) interface and the Data Link Layer (DLL) messaging and protocols (OSI layers 1 and 2) that enable communications between compliant transponders and managed OSP power equipment. Edition 2.0 incorporates updates from ANSI/SCTE 25-3 v1.1 (2005), aligns Clause 7 with ANSI/SCTE 110 (2005), and adds an informative Annex A on the hybrid management sub-layer (HMS).

Key topics and technical requirements

• Scope and architecture: Reference architecture for forward and return channels in HFC outside plant monitoring.
• Physical layer (PHY): Connector types (e.g., RJ‑45 references), interface signals, line balance, cable length limits, transponder power, indicators and alternative PHY options.
• Data Link Layer (DLL): Packet structure, start/end framing, source/destination addressing, identification, datagram formats, checksums and DLE sequences.
• Timing and synchronization: Message timing, transmission requirements and interaction rules to ensure robust communications.
• Datagram set and commands: Defined DLL datagram types and commands such as Get_Configuration, Get_Power_Supply_Data, Power_Supply_Control, Get_Generator_Data, Generator_Control and standard responses (Request_Processed, Invalid_Request).
• Interoperability and compliance: Interface and implementation compliance requirements, revision control and reserved address ranges.
• Informative material: Annex A covering the hybrid management sub‑layer (HMS) document family and guidance for implementers.

Applications and practical value

This standard is intended for use in the design, implementation and operation of HFC network management systems that monitor and control OSP power equipment. Practical applications include:

• Designing PSTIB‑compliant transponders, power supplies and interface hardware
• Implementing firmware/software for DLL messaging, datagram parsing and command handling
• Enabling interoperable remote monitoring and control of battery strings, generators and rectifiers in HFC outside plant
• Specifying cabling, connectors and RS‑485 style interfaces for field installations
• Integrating OSP power monitoring into broader Hybrid Management Sub‑Layer (HMS) or network management systems

Who should use this standard

• Cable network operators and system architects
• Equipment manufacturers (transponders, power supplies, monitoring modules)
• System integrators and network management software developers
• Field engineers and test/validation teams ensuring interoperability and compliance

Related standards and references

• ANSI/SCTE 25‑3 (v1.0 → v1.1) - incorporated updates
• ANSI/SCTE 110 (2005) - basis for alternative PHY clause
• IEC 60728 series - broader HFC cable network standards

Keywords: IEC 60728-7-3, PSTIB, HFC OSP, power supply to transponder interface bus, hybrid fibre coax, PSTIB datagrams, data link layer, physical layer, OSP power monitoring.