Interoperability can be defined as the ability of a user to seamlessly purchase, deploy and use a system form multiple suppliers or the ability of a two or more systems or components to exchange information and to periodically use the information that has been exchanged.
There are several levels of interoperability:
- Meter level: look and feel, mechanical mount, operation, protocols
- System level: billing, tokens, vending standard, infrastructure, protocols
- Application level: prepayment, post- payment, smart metering
Interoperable systems normally conform to one or more open standards.
An open standard is defined as a standard that is available to any person wishing to develop a product that conforms to that standard, with no restrictions such as patents and trademarks, or reasonable negotiable licences to use such a standard. Examples of organizations that publish open standards are:
The use of the open standard may be subject to the purchase of the standard from the organization, or membership of the organization.
The STS uses interoperable standards, i.e. IEC62055-41, IEC62055-51, and IEC62055-52, as well as several companion specifications, thus making the STS products interoperable. Any system that uses these standards will be able to function between manufacturers. So, a meter purchased from one manufacturer will function correctly with a vending system form another manufacturer, provided that both are certified as STS compliant.