What is STS?

Standard Transfer Specification (STS) is a standard regarding the manufacture of prepaid meters as well as the vending system used to vend prepaid vouchers. STS has become the standard to which all prepaid meters in the industry have to be manufactured using standard cryptography and cryptographic keys. It is thus imperative that all prepaid meters need to be able to function on all the different vending systems available and that all vending systems need to use the same standard to be able to accept all the prepaid meter variants.

Historically in electricity pre-payment, distributors focused on the pre-payment unit, rather than on the vending system and infrastructure required to support the dispenser. Typically the specifications needed for vending systems and the development of vending systems was left to the various pre-payment unit manufacturers. As a result, numerousvending systems were developed which were not compatible with each other.

The most significant consequence of this incompatibility was the inabilty of the vending system of one manufacturer to vend to the prepayment unit of another. Consequently, distributors purchasing prepayment units from different manufacturers, had to purchase separate vending systems for each type of unit. This proved to be expensive, ineffeicient and operationally inconvenient and complex.

The development of STS (Standard Transfer Specification) was initiated by Eskom, since they were purchasing numerous pre-payment units for various municipalities from different manufacturing companies which consequently led to the purchasing of different vending systems for the operation of these units. The introduction of STS was the only means of ensuring that the electricity pre-payment tokens issued issued by a vending system of one manufacturer could also be used on a pre-payment unit of a different manufacturer. This has led to all pre-payment units, even though different in looks and manufactured by different companies, all functioning using the same STS encryption technology for the production of vouchers.

The Standard Transfer Specification (STS) has become recognised as the only globally acccepted standard for pre-payment systems, ensuring inter-operability between system components from different manufacturers of pre-payment systems. The application of the technology is licensed through the STS Association, thus ensuring that the appropriate encryption key management practices are applied to protect the security of the pre-payment transactions of utilities operating STS sytems. It has become established as a worldwide standard for the transfer of electricity pre-payment tokens since its initial introduction in South Africa in 1997.
The success of STS lies in that it is:
Internationally recognised, having been published as an International Standard by the IEC in 2007. An open standard, allowing STS-compliant equipment from any number of suppliers to be integrated into an electricity sales system. A secure standard - the encrytion technology used has proved to be extremely robust and simple for customers to use.
One of the main concerns that investors have when installing prepaid meters are:
Question: What happens if the supplier of the vending system supporting my meter is liquidated? 
Answer:    If the prepaid meter that you have installed is STS Compliant, it can be switched to any other vending system available at the time. Currently there are 4 different systems available in South Africa.
Question: What can I do if I am not happy with my current service provider?
Answer:   All current service providers and manufacturers belong to the STS Association. The STS Association is backed by Eskom and compels all members to make codes available for an exchange of vending systems to take place at any given time.
Question: Do I need to purchase any software for the operation of my meters?
Answer:   STS standards require that all vending systems are internet and SMS based and are able to be accessed from anywhere around the world.
The Standard Transfer specification has found widespread application. Initially created in South Africa, it has subsequently spread to many developed and developing countries. To date, over 10-Million STS-compliant meters have been installed at 400 utilities in 30 countriesaround the world. If you want to read more about STS, please visit: //www.sts.org.za/


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