CONTENTS

 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