BS 8521:2009

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Information transfer
5 Communication
6 Speech path and system control commands
7 Programming
8 Remote access to local unit and controller
  (incoming calls)
Bibliography

Describes requirements for the transfer of information and controls within a social alarm system, by means of dual-tone multi-frequency (DTMF) tone signals passing between site control or local equipment and an alarm receiving centre via the public switched telephone network (PSTN) supporting voice traffic conforming to ITU-T Recommendation G.711.

This British Standard specifies requirements for the transfer of information and controls within a social alarm system, by means of dual‑tone multi‑frequency (DTMF) tone signals passing between site control or local equipment and an alarm receiving centre via the public switched telephone network (PSTN) supporting voice traffic conforming to ITU‑T Recommendation G.711 [1].

The standard specifies an in‑call protocol which supports the 300 ms maximum round trip delay specified in the UK National Transmission Plan [2] for connections over the fixed network.