This Technical Bulletin outlines the necessary preparations for NSI-approved companies in response to the migration from the National Public Switched Telephone Network (PSTN) to an ALL IP communications network, which is expected to be completed by 2025. It highlights the potential impacts on electronic security and fire alarm systems, emphasizing the need for companies to inform customers about the migration, assess the compatibility of existing signaling devices, and consider backup power solutions. Mandatory actions for compliance will be evaluated during audit visits to ensure readiness for the transition.