1
Scope
2 Normative references
3 Definitions and abbreviations
4 Group Audio Terminals types
5 Speech transmission
characteristics
5.1 Handset mode
5.2 Headset mode
5.3 Hands-free mode (single-user
facilities)
5.4 Hands-free mode (multiple-users
facility)
5.4.1 Receiving volume control and sensitivity adjustments
5.4.2 Sensitivity-frequency responses
5.4.3 Loudness Rating
5.4.4 Echo path loss characteristics
5.4.5 Distortion
5.4.6 Out‑of‑band requirements
5.4.7 Noise
5.4.8 Delay
Annex A – Objective
measurement methods for hands-free, multiple users GATs
A.1 Introduction
A.1.1 Testing arrangements
A.1.2 Test signals levels
A.2 Testing of transmission
requirements
A.2.1 Sensitivity‑frequency
response
A.2.2 Loudness rating
A.2.3 Terminal Coupling Loss
Appendix I – Practical
in-situ audio alignment procedure for multiple-users hands-free GATs
I.1 Introduction
I.2 Audio alignment and sensitivity‑frequency
characteristics
I.2.1 Sending
I.2.2 Receiving