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PD IEC TR 62056 โ Electricity Metering Data Exchange Technical Report Series (Wide Area Network PSTN Communication and DLMS Server)
Part 41: Data exchange using wide area networks โ Public switched telephone network (PSTN) with LINK+ protocol; Part 52: Communication protocols management distribution line message specification (DLMS) server
๐ PD IEC TR 62056 is the UK adoption of technical reports from the IEC TR 62056 series, with UK responsibility held by Committee PEL/13 (Electricity meters). The series addresses electricity metering โ data exchange for meter reading, tariff and load control, published in its early versions (1998/2002) during the IEC renumbering transition. This batch contains two documents: Part 41 specifies data exchange using wide area networks โ the public switched telephone network (PSTN) with the LINK+ protocol, and Part 52 specifies the communication protocols management distribution line message specification (DLMS) server. These technical reports provided foundational protocol and object-model definitions for early automatic meter reading (AMR) and metering data communication systems.
๐ก The IEC 62056 family (in its modern form, DLMS/COSEM) is the international standards system for electricity metering data exchange: through a unified “object model + application layer protocol + communication medium adaptation” architecture, it achieves interoperability between meters and reading systems from different manufacturers. These early technical reports are an important step in that evolution.
1. Scope and Series Structure ๐
The IEC 62056 family is organised by “data exchange application”: it covers the common architecture for meter data exchange (object model, communication protocol, medium-related specifications) and accompanying technical reports. This series contains two documents:
| Document | Subject | Content | Year |
|---|---|---|---|
| PD IEC TR 62056-41:1998 (2002) | Wide area network data exchange | Data exchange using wide area networks: PSTN with LINK+ protocol | 1998/2002 |
| PD IEC TR 62056-52:1998 (2002) | DLMS server | Communication protocols management DLMS server | 1998/2002 |
โ ๏ธ This series is a first-edition UK publication issued in 2002, an early metering-communication technical document. Modern metering communication generally follows the DLMS/COSEM specifications (IEC 62056-4x/5x/6x series); use the current edition for engineering applications.
2. Part 41 โ Wide Area Network PSTN and LINK+ Protocol ๐
Part 41 specifies the architecture and protocol for electricity metering data exchange over the public switched telephone network (PSTN). Core content includes:
- Basic vocabulary: definitions of fundamental terms and concepts in metering data exchange, establishing a common language;
- Layers and protocols: the layered structure of communication and the protocol stack, specifying the transmission mechanism of the LINK+ protocol over PSTN;
- Specification language: the method for describing protocols and data for conformance implementation;
- Internetwork interoperability: PSTN dial-up as the bearer for wide area data exchange, supporting the master station (reading centre) polling meters via modems;
- Standards and accompanying references: linking with other protocol specifications in the IEC 62056 family to ensure consistency and compatibility of data exchange.
๐ก Before broadband and cellular communication became widespread, PSTN dial-up was the main bearer for AMR: the reading centre polled concentrators/meters individually or in batches over the telephone network to remotely read tariff, load and event data. The LINK+ protocol defines link-layer encapsulation and error control within the dial-up session.
3. Part 52 โ Communication Protocols Management DLMS Server ๐
Part 52 specifies the management objects of the DLMS (Distribution Line Message Specification) server for electricity billing data exchange. Core content includes:
- Conformance block: defines the conformance scope of protocols and functions supported by the server, indicating the services a client can rely on;
- DLMS objects: specifies the set of management objects in the server, typically including VDEManagement, DSManagement, VAAManagement and other objects, used to manage communication sessions, data access and protocol behaviour;
- Variable objects: specifies the object-oriented representation of metering data variables (energy, tariff, status, etc.) accessible through DLMS;
- Companion standard: explains the relationship with other parts of the family (e.g. communication protocol management), ensuring interoperability between different server implementations.
โ ๏ธ The DLMS server object model is the precursor of the DLMS/COSEM architecture: it uniformly models “metering data + communication management” as addressable objects, allowing a master station to read data from different meter types with consistent semantics. The modern COSEM object model (OBIS codes) evolved from this basis.
4. Engineering and Application Practice ๐ ๏ธ
- ๐ Protocol understanding: when integrating or maintaining early AMR systems, understanding the PSTN dial-up session, LINK+ link layer and DLMS object addressing is the basis for debugging and troubleshooting.
- ๐ก Medium planning: for metering communication still carried over PSTN, assess telephone line availability, dial-up latency and the effect of concurrent polling on the reading cycle.
- ๐ค Interoperability verification: check the conformance blocks and object support scope of the master station (reading centre) and meter (DLMS server) to avoid object access incompatibility causing read failures.
- ๐ Upgrade migration: plan the migration path from early PSTN/DLMS to modern DLMS/COSEM, cellular and broadband communication, ensuring continuity and security of metering data.
5. Frequently Asked Questions โ
โ Q: What do Parts 41 and 52 address respectively?
A: Part 41 addresses “how data is transmitted” โ specifying the wide area network (PSTN) bearer and LINK+ protocol transmission mechanism; Part 52 addresses “how data is managed” โ specifying the DLMS server object model and communication protocol management.
A: Part 41 addresses “how data is transmitted” โ specifying the wide area network (PSTN) bearer and LINK+ protocol transmission mechanism; Part 52 addresses “how data is managed” โ specifying the DLMS server object model and communication protocol management.
โ Q: What is the LINK+ protocol?
A: LINK+ is a link-layer protocol for PSTN dial-up data exchange, defining encapsulation, transmission and error-control mechanisms within the dial-up session, providing a reliable data link between the metering master station and meters.
A: LINK+ is a link-layer protocol for PSTN dial-up data exchange, defining encapsulation, transmission and error-control mechanisms within the dial-up session, providing a reliable data link between the metering master station and meters.
โ Q: What is the relationship between the DLMS server and COSEM?
A: DLMS (Distribution Line Message Specification) is the application-layer protocol system for metering data exchange; the DLMS server objects in this document are its early implementation. The modern COSEM object model (OBIS codes and object classes) evolved from it in a standardised way.
A: DLMS (Distribution Line Message Specification) is the application-layer protocol system for metering data exchange; the DLMS server objects in this document are its early implementation. The modern COSEM object model (OBIS codes and object classes) evolved from it in a standardised way.
๐ Q: Are these early technical reports still useful today?
A: They are still valuable for maintaining early AMR/PSTN systems and understanding protocol evolution; new systems should follow the current DLMS/COSEM (IEC 62056) specifications and corresponding communication technologies.
A: They are still valuable for maintaining early AMR/PSTN systems and understanding protocol evolution; new systems should follow the current DLMS/COSEM (IEC 62056) specifications and corresponding communication technologies.