BS 8521:2009

BS 8521:2009 Specification for dual-tone multi-frequency (DTMF) signalling protocol for social alarm systems

BS 8521 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.

BS 8521 specifies an in-call protocol which supports the 300 ms maximum round trip delay specified in the UK National Transmission Plan for connections over the fixed network.

Contents of BS 8521:

• Foreword
• Introduction
• Scope
• Normative references
• Terms and definitions
• Information transfer
• Communication
• Speech path and system control commands
• Programming
• Remote access to local unit and controller (incoming calls)
• Bibliography
• Diagrammatic representation of an example of an alarm transmission protocol
• Diagrammatic representation of an example of local unit and speech communication
• Diagrammatic representation of an example of programming
• ARC initiated communications sequence with controller
• ARC initiated communications sequence with local unit and controller