IEC 62055-51:2007

Overview

IEC 62055-51:2007 defines the physical layer protocol of the Standard Transfer Specification (STS) for one‑way numeric and magnetic card token carriers used in electricity metering payment systems. The standard specifies how units of credit and management information are encoded at a point‑of‑sale (POS) and decoded by STS‑compliant payment meters. It is part of the IEC 62055 series that establishes interoperable, secure token-based vending for utilities.

Key topics

• Scope of the physical layer: Encoding and decoding rules for token data exchanged between POS systems and payment meters using one‑way token carriers (magnetic cards and numeric token carriers).
• TokenCarrierDataUnit (TCDU): Defines the data elements and structure that must be carried on token media for reliable transfer of credit and management messages.
• Magnetic card encoding: Rules for formatting STS tokens on magnetic stripe tracks (references ISO/IEC 7811/7813 standards).
• Numeric token encoding: Rules for representing token data as numeric tokens (decimal representations and conversions used by meters).
• Interoperability and procurement: Guidance (including Annex A) on selective compliance and procurement options so buyers and manufacturers can ensure compatibility.
• Security and key management: STS framework provides secure message formats and cryptographic key management practices (see IEC 62055-41 for application‑layer security details).
• Normative references: Cross‑references to IEC 62055‑41 (application layer), IEC 62055‑31 (meter requirements) and ISO/IEC identification card standards.

Note: the standard records that some numeric token carrier techniques may be subject to patent rights; licensing information is registered with the IEC.

Applications

• Electricity utilities: Enabling interoperable vending of prepaid credit across multiple POS vendors and meter manufacturers.
• Meter manufacturers: Implementing STS‑compliant decoders to accept magnetic and numeric tokens in payment meters.
• POS and vending equipment vendors: Encoding STS tokens correctly onto magnetic cards or printing numeric token carriers for sale to customers.
• Other utilities: Adaptable for prepaid systems for water and gas where token‑based prepayment is used.