BS 7940:1999
Current
The latest, up-to-date edition.
Analogue PSTN terminal support interface
Hardcopy , PDF
English
15-10-1999
Committees responsible
Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Physical connection requirements
5 D.C. feed conditions
6 Seize signal
7 Clear signal
8 Impedance
9 Transmission
10 Signalling
11 Ringing
12 Supervisory signals
13 Optional functions
14 Information required for test purposes
Annex A (normative) Test methods
Annex B (informative) Reasons for inclusion of requirements
Annex C (informative) Support for ALASS
Bibliography
Figure 1 - Apparatus types
Figure 2 - Apparatus state transition diagram
Figure 3 - PTRP example
Figure 4 - Reference impedance Zref
Figure A.1 - Basic test arrangement
Figure A.2 - Circuit for balance about earth
Figure A.3 - Circuit for transmission loss measurement
Figure A.4 - 3-wire ringer test circuit
Figure A.5 - 2-wire ringer test circuit
Figure A.6 - Feed bridge circuit
Table 1 - Apparatus types
Table 2 - Frequency response limits
Table 3 - Frequency response limits
Table 4 - Variation of loss with signal level
Table 5 - Recommended relative delay limits
Table 6 - Information required for test purposes
Table A.1 - Tolerances on measurements
Table A.2 - Tolerances on stimuli
Table A.3 - Requirements for test conditions
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