As the UK advances towards a full transition to ALL-IP services, we are collaborating closely with communication providers, the BSIA, alarm transmission system (ATS) providers, and relevant government departments through the Fire & Security Advisory Board (F&SAB). This coordinated effort seeks to ensure that customers with phone-line-dependent alarm systems transition smoothly without service disruptions. To support this objective, we kindly request your cooperation. We ask that you provide the inbound ARC receiver numbers associated with any of your alarm signalling solutions that currently use PSTN or ISDN phone lines. This information will be shared with communication providers to help them identify customers whose equipment relies on these numbers. When an IP migration is proposed, communication providers will flag the need for customers to consult with their alarm installers to facilitate a secure transition. The BSIA will act as the central repository for these numbers and we encourage you to submit your receiver numbers directly to them using the email address technical@bsia.co.uk and in the following format: ARC name (or identifier) PSTN receiver number(s) ISDN receiver number(s) The BSIA has stated that the data provided will not be shared wider than the CPs (communications providers) and will not be available to other ARCs. The data will be used solely for the purpose of line ownership (by the CP) and to identify where an alarm signalling device may be connected to their customer’s premise. No data-sharing agreement is considered necessary as the request is for inbound ARC numbers only and not customer-called lines. By consolidating this information, we can streamline communication and ensure all stakeholders are aligned in the transition process. If there is any additional information you believe would be beneficial to include in this process, please feel free to share it with us or the BSIA. We appreciate your cooperation and prompt attention to this matter. Should you have any questions or require further clarification, please do not hesitate to contact us.