Introduction to the STS

This document provides a brief introduction to the Standard Transfer Specification.

STS is 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. STS is not limited to this application (see the section: Future enhancements), but because of the wide interest in this area, this document describes the electricity application. STS is a South African industry specification described in *NRS 009-6, section 6 to 9, and part 7 which are being considered for publication as publicly available standards through IEC TC 13 working group 15 †.


The STS specification does not specify any physical characteristics (such as shape or size) of a prepayment meter. Please note that only the following three specification documents are applicable for STS certification: NRS009-6-6:2002; NRS009-6-7:2002 and NRS009-6-9:1997 - any other documents linked from the STS website are for general background information (or as implementation examples) only.