Standard Transfer Specification Association
Standard Transfer Specification Association

The Standard Transfer Specification is the global standard for the transfer of electricity and other utility prepayment tokens, ensuring inter-operability between system components from different manufacturers.


There are only 3 years left to ensure that all STS meters are rolled over before 24 November 2024

What is the STS?

The Standard Transfer Specification (STS) describes a secure message system for carrying information between a point-of-sale and a meter, and is currently finding wide application in electricity metering and payment systems.

Certified Products

All products that are required to display the STS logo must be certified by a STS accredited test house. Read more on the certification process or view the list of Certified Products.

STS - A Beginners Guide

A Step-by-Step guide on how to benefit from the wide range of features that STS offers. Interoperability, high level cryptographic security, and much more. 

STS Edition 2

The latest edition of the specifications, STS Edition 2, not only maintains backward compatibility to the current systems in use, but more importantly, it enables the use of the latest state of the art cryptographic algorithms, while also introducing many new features in order to keep abreast with modern metering technologies. 

TAKE ACTION NOW and prepare for the key change operation so you don’t get left behind.

Manufacturer Codes

Paid up members of the association can acquire a Manufacturer Code if they have metering products that are ready for compliance certification. The Manufacturer Code is a unique four digit numerical code that you need to encode into your product firmware before compliance testing can commence.


The members of the association are companies and utilities involved in the manufacture, supply or operation of STS based systems. Membership can be obtained by signing our membership agreement and paying the prescribed joining and annual membership fees. 

TID Rollover

The Token Identifier is a 24 bit field, contained in STS compliant tokens, that identifies the date and time of the token generation. It is used to determine if a token has already been used in a payment meter. The TID represents the minutes elapsed since the 1st January 1993. The incrementing of the 24 bit field means that at some point in time, the TID value will roll over to a zero value. 

Virtual Secure Module

The Virtual Security Module (VSM) is to be used for testing purposes only. The use of the VSM or any other software security module  in a live system will render the system non-STS compliant.