Foreword
Introduction
1. Scope
2. Normative references
3. Definitions
4. General system requirements
5. System technical requirements
6. Installation requirements
7. System operation
Annex A (informative) - Measurement of speech intelligibility
Annex B (normative) - Intelligibility measurement methods
Annex C (normative) - Attention-drawing audible signals
Annex D (informative) - Bibliography