TS IEC 60050-191+A1+A2

TS IEC 60050-191+A1+A2 is a terminology standard for electrotechnics that gives a common language for dependability and quality of service. This part clarifies the core concepts used to describe how well a system or service performs its intended function over time.

Technical meaning of the terms

The standard specifies terms and definitions related to dependability and quality of service. In general technical use, dependability covers ideas such as reliability, availability, maintainability, and supportability, while quality of service focuses on the level of service delivered under defined conditions. By fixing the vocabulary, the document helps engineers, specifiers, and analysts avoid ambiguity when discussing performance, failure behaviour, maintenance planning, and service continuity.

Why the distinction matters

Dependability and quality of service are closely related but not identical. Dependability is centered on the technical ability of an item, system, or process to perform as required, whereas quality of service is often judged from the service user's perspective and may involve measurable service attributes such as continuity, responsiveness, or consistency. Using these terms consistently is especially important in electrical and electronic systems where a component-level failure can affect wider system availability and customer experience.

This TSE listing corresponds to the international electrotechnical vocabulary chapter based on IEC 60050-191:1990+A1:1999+A2:2002. As a vocabulary document, it defines concepts and relationships; it does not, by itself, establish product test limits or mandatory performance requirements.