In 2025, British Telecom plans to shut off its ISDN and PSTN services in favor of modern technologies like VoIP. ISDN, or Integrated Services Digital Network, was a technology that promised to revolutionize telecommunications, but it failed to gain widespread adoption due to its high cost and lack of clear benefits for the average consumer. Although ISDN found some niche uses in industries like recording studios and radio stations, it was ultimately overshadowed by alternatives such as cable and DSL. The legacy of ISDN serves as a reminder that bottom-up innovation driven by consumer needs often outperforms top-down solutions imposed by the telecom industry.
https://tedium.co/2024/01/12/isdn-history-retrospective/