https://business.bt.com/help/article/phone-line-and-services/move-from-traditional-lines-to-the-cloud/the-pstn-and-isdn-switch-off-what-it-means-for-you/
The PSTN and ISDN switch-off: what it means for you | BT Business
If you're using a traditional phone line, you'll need to move to a fully digital service by the end of January 2027 to safeguard your services. Learn more.
isdn switch off
https://www.computerweekly.com/microscope/news/252500776/Significant-number-of-SMEs-unaware-of-looming-ISDN-switch-off/
Significant number of SMEs unaware of looming ISDN switch-off | Microscope
The 2025 ISDN switch-off is moving closer and as local exchanges are marked out for transition, Spitfire Network Services has exposed high levels of ignorance...
isdn switch offsignificantnumbersmesunaware