The document is a technical bulletin from the National Security Inspectorate regarding the publication of BS EN 50131-1:2006 – A3:2020, which outlines requirements for intrusion and hold-up alarm systems. It highlights the publication of amendment 3 in June 2020, details the implementation timeline for compliance, and notes significant changes, including updates to remote access protocols and the introduction of new definitions and requirements. The bulletin also emphasizes the importance of compliance with the standard as it relates to future editions of PD 6662 and includes clarifications on various technical aspects of alarm systems. Manual review may be needed for complete details on all changes introduced.