Standard Transfer Specification Association
Standard Transfer Specification Association

Definitions: GENERAL

APDU - ApplicationProtocolDataUnit

The APDU is the data interface between the MeterApplicationProcess and the application

layer protocol. [IEC62055-41]

ASN1 - Abstract Syntax Notation One

Abstract Syntax Notation One is a standard interface description language for defining data structures that can be serialized and deserialized in a cross-platform way. It is broadly used in telecommunications and computer networking, and especially in cryptography. 

[Wikipedia] [ITUT –TREC X690 2008-11]

A-XDR - Adapted External Data Representation

External Data Representation (XDR) is a standard data serialization format, for uses such as computer network protocols. It allows data to be transferred between different kinds of computer systems.[Wikipedia], [ IEC 61334-6 Ed 1:2000]

BER - Basic Encoding Rules of ASN1

The Basic Encoding Rules (BER) are a set of Abstract Syntax Notation One encoding rules that define a specific way in which information may be encoded in a binary form. It is used as the underlying mechanism for encoding messages.

CC - Country Code

A 3-digit code allocated uniquely to each country. [ISO3166]

CDV - Committee Draft for Vote

A draft of a specification, developed by a working group of the STSA, that is sent out to the general membership for the purposes of voting on its acceptance for publication. 

CIS - Customer Information System 

A Customer Information System (CIS) is a system used by an organization to assist users to obtain customer information efficiently.

​COC - Code of Conduct

A document, published by the STSA, that sets out an STS member shall conduct his business relating to the STS, and membership thereof.

COP - Code of Practice

A document, published by the STSA, that sets out certain rules, regulations, and behaviour, that an STS member shall follow.

​CTS - Conformance Test Specification 

A set of test specifications used for conformance testing by an STSA approved test house.

HHU - HandHeldUnit 

A hand held device used for data acquisition, token entry, or general communication to a payment meter or other device.

IIN - IssuerIdentificationNumber

The IIN is a unique 4 or 6 digit number that defines a domain under which further DRN values may be issued for use within this defined domain.


The ability of a user to seamlessly purchase, deploy, and use a system from multiple suppliers. Or, the ability of 2 or more systems/components to exchange information and to periodically use the information that has been exchanged [IEEE Standard Computer Dictionary]. 

The STS specifications ensure interoperability between STS certified systems - This means that any STS system must be able to work with any other STS system (meters and vending). 

MFO / VMFO - MeterFunctionObject / VirtualMeterFunctionObject

A MeterFunctionObject (MFO) is an object-oriented specification that encapsulates a certain functionality of a payment meter. Each MFO is defined in a companion specification and allocated a unique FunctionObjectIdentificationNumber (FOIN). [IEC62055-41]

MFR - Manufacturer 

In the STS context a manufacturer is an entity that manufactures payment meters, point of sale software, or security modules for use in the STS domain. 

MIS - Management Information System

A management information system is an information system used for decision-making, and for the coordination, control, analysis, and visualization of information in an organization and marketing. The study of the management information systems involves people, processes and technology in an organizational context. [Wikipedia]

​NWIP - New Work Item Proposal

A document, generated by a member or user of the STS standards, that outlines a proposal for a change to, or generation of, a specification. The NWIP document is circulated to an STSA Working Group, who then ascertains whether this is a viable proposal or not.

The Working Group generates a report to the board of the STSA specifying whether the proposal should receive further action (i.e. perform the work of the proposal), or cancel the proposal. In either event, the NWIP proposer is informed in writing of the outcome.


An open standard is a standard that is publicly available and has various rights to use associated with it and may also have various properties of how it was designed. There is no single definition, and interpretations vary with usage. [WIKIPEDIA]

​OSI - Open Systems Interconnection

The OSI Model (Open Systems Interconnection Model) is a conceptual framework used to describe the functions of a networking system. The OSI model characterizes computing functions into a universal set of rules and requirements in order to support interoperability between different products and software. [Forcepoint]

​PLC - Power Line Carrier

Power-line communication (also know as Power Line carrier - PLC) carries data on a conductor that is also used simultaneously for AC electric power transmission or electric power distribution to consumers. Various data rates and frequencies are used in different situations.  [Wikipedia] 

TCDU - TokenCarrierDataUnit

A TCDU is composed of protocol-specific control information and user data for the token carrier in a payment meter. [IEC62055-41] [Wikipedia]

TDT - TokenDataType

The TokenDataType indicates the data format of the transmitted token. This could be, for example a 66 bit token, or a bulk token. [STS101-2]

TI - Tariff Index

The tariff index of a payment meter is defined as a two-digit number in the range 00 to 99. This number is used to indicate which charge tariff is in use by the payment meter. It also diversifies the meter key generated by the decoder key generation algorithm. [Ref: IEC62055-41]

UUT - Unit Under Test

A product currently undergoing testing.

WG - Working Group

A group of technical or non-technical specialists formed from time to time to define/develop/alter specifications, and report their findings to the board of the STSA.