Standard Transfer Specification Association
Standard Transfer Specification Association


The specifications relevant for the implementation of an STS compliant system are listed in the table below. The table also shows where the specifications may be obtained from.

Companion specifications are enhancements to the international standards, developed by STSA working groups and published by the STSA, which are destined for inclusion into future releases of the international standards and may be used for development and enhancement of payment systems.

Which edition of a specification should be used?

It is imperative that the latest version of a specification be used for development. The test houses will always use the latest version for compliance testing of a product. If there is any uncertainty into which version is the latest, you may visit the STSA website at, or contact technical support.

Specification Number

Title and Description

Specification Type

Available from

IEC62055-41 Ed2 2014Electricity metering – Payment systems –Part 41: Standard transfer specification (STS) – Application layer protocol for one-way token carrier systemsInternational StandardIEC Webstore
IEC62055-51Electricity metering – payment systems – Part 51: Standard transfer specification (STS) – Physical layer protocol for one-way numeric and magnetic card token carriersInternational StandardIEC Webstore

IEC62055-41 - Changes from Edition1 to Edition 2

Edition 2 of the IEC62055-41 was published in 2014. The changes from Edition 1 to Edition 2 are summarised below.

IEC62055-41 - Changes from Edition 2 to Edition 3

Edition 3 of the IEC62055-41 specification is due for publication in 2018. Edition 3 of the IEC62055-41 specification is due for publication in 2018.