Metering solutions for every distributor
Utiliflex offers a full line of AMI, prepaid electricity meters, and enclosures. We support leading manufacturers including Aclara, Clou, Conlog, Elster, Echelon, Itron, and Landis+Gyr.
Standard Transfer Specification (STS) is a secure message system for carrying information between a point-of-sale and a meter, and is currently widely used in electricity metering and payment systems. STS is not limited to the electricity application.
Currently used in 84 countries, the application of the technology is licensed through the STS Association, ensuring that the appropriate encryption key management practices are applied to protect the security of prepayment transactions.
The STS has been adopted by IEC as IEC 62055 parts -41and -51 as the international standard for prepaid electric metering
STS is critical to successful operation of any payment system. STS fully addresses key issues of security and interoperability of equipment supplied by different manufacturers. Security issues are of prime importance to the utility supplier and the consumer.
● Fraudulent generation of tokens from hit-and-miss attempts at entering the correct number
● Fraudulent generation of tokens from a stolen vending station
● Fraudulent generation of tokens from legitimate vending stations outside of the utility's area
● Fraudulent use of tokens which have already been used
● Tampering of legitimate tokens (e.g. to change the value)
STS provides the facility of generating (e.g.credit transfer) tokens which can only be used by the intended meter, and furthermore in the case of credit tokens, can only be used once in that meter.
● Use of advanced encryption techniques, which are hidden from the consumer
● Use of very secure key management procedures, including how keys are generated and transported
● Required functionality at both the vending station and the meter
Compatibility issues between systems performing the same or similar functions creates interoperability issues for systems from different manufacturers or suppliers.
STS is an open-system specification that defines transfer tokens from a vending system from any supplier to be used in STS-compliant meters from any supplier. STS also specifies vending station functionality and meter response to certain transfer numbers in order to achieve interoperability, allowing utilities to mix and match equipment from suppliers of their choice.
● Ensuring that all manufacturers make encryption keys available to all other manufacturers at the request of the utility using the equipment
● Accrediting and maintaining a list of equipment test laboratories to ensure correct STS functionality of equipment
● Ensuring consistent manufacturer identity codes and meter serial numbers
The STS Association assures the security of STS systems by:
● Obtaining the manufacturer agreement on rules regarding the handling of confidential information and procedures
● Approving equipment and processes for generating and transferring encryption keys
STS can easily be expanded to include other utilities such as gas and water. STS transfer numbers, rather than being hand carried, may be transmitted using various communication standards such as DLMS.
The STS algorithm is undergoing its first major update since its creation in the mid-1990s. To differentiate the two systems, the legacy algorithm is referred to as STS4 and the new algorithm is STS6.
The STS4 algorithm uses a fixed "base date" of 1993 for time calculations. Given space limits within the token technology (20-digits), the maximum date that can be encoded is November 2024. For this reason, the STS Association has been working for the last several years to create a new algorithm that allows for a floating base date.
This new version, called STS6, is now available and our Juice Prepaid software interface code has been certified to use the new hardware. More information is available at tidrollover.com.
STS meters have a register that holds the base date. The only difference at the meter level between STS4 andSTS6 is whether this base date is 1993 or 2014. However, changing the base date in a meter requires a "key change", which is done by entering two tokens. Every meter with a 1993 base date will require key change tokens be entered before 2024. Therefore, it is prudent to go ahead and update vending systems so that meters procured going forward can be programmed at the factory with the 2014 base date and avoid the need to do a manual key change. Given the logistical challenges of doing a key change at each meter, we strongly recommend updating to STS6 to minimize the challenges.
STS6 requires new hardware encryption modules using the STS6 firmware, or for older modules to be returned to the factory for reflashing. Our policy is to replace the hardware rather than re-flash old modules given improvements in throughput speed and to ensure reliability. In conjunction with the new hardware, Utiliflex will update the production Juice vending system code to use the STS6 compliant connectors for the new hardware.
While the update will be largely seamless aside from the need to do the key changes on STS4 meters, there are enhancements on the Juice Prepaid side that improve performance, scalability, and resiliency, especially with cloud deployments and our SaaS product given changes in the underlying hardware technology and software architecture. But most importantly, upgrading will allow legacy STS meters to work for decades into the future.
We're eager to help you create a better metering solution. Let's talk today.