PD 6571:1992

Committees responsible
Preface
Foreword
Section one. General
1 Scope
2 Abbreviations, definitions and notation
3 General requirements and test conditions
4 Information to be provided by the supplier
5 Electrical network connection methods (speech
    apparatus)
Section two. Electrical characteristics of apparatus
6 Apparatus on-line (non-signalling state)
7 Transmission process
Appendices
A General conditions of test
B Methods of test
Tables
1 Not assigned
2 Limits of sending sensitivity for line lengths up to
    and including 3 km
3 Limits of sending sensitivity for line lengths in
    the range over 3 km to 7.5 km
4 Limits of noise levels for noise criterion curve
    NC 15
5 Data required to calculate Z
6 Psophometric weighting characteristics
Figures
1 Not assigned
2 Measurements of free field sound pressure used in
    the determination of sending sensitivity
3 Physical test arrangement for determining the
    sending characteristics
4 Limits of sending sensitivity for line lengths up to
    and including 3 km
5 Limits of sending sensitivity for line lengths in
    the range over 3 km to 7.5 km
6 Physical test arrangement for determining the
    receiving characteristic
7 Noise criterion curve NC 15
8 Dimensions of test table
9 Position of LST
10 The local telephone system
11 D.C. excited test circuit
12 Axes used in the determination of free field
    conditions for 1 m radius sphere

Specifies requirements for loudspeaking facilities incorporated in apparatus for connection to a single exchange line or to systems connected to the public switched telephone network. Not applicable to apparatus for connection to shared service lines nor to apparatus for connection between a TJF of a PBX and the PSTN lines of a PBX. Only applies where the apparatus containing the loudspeaking facility also gives either integral handset telephony or the capability of associated handset telephony. Coverage includes: abbreviations, definitions and notation; apparatus on-line (non-signalling state); transmission process. Also includes appendices, tables and diagrams.