[bewo001]

I worked at an ISDN adapter company in the late 1990s. Apparently, one customer a couple of years earlier did use ISDN as their LAN technology. Each PC with an adaptor (to the joy of my employer, this customer was not small), using the PBX as network switch. I have no idea what software they used. Probably some CAPI-based file transfer. The extended version of that, using ATM-based BISDN, was the telcos' vision of networking.