I did my training at Deutsche Telekom, and our instructors told us a story of an ISP that tried to sell a flatrate working over the D-channel; apparently they h

I did my training at Deutsche Telekom, and our instructors told us a story of an ISP that tried to sell a flatrate working over the D-channel; apparently they had some reliability issues and did not last long. That must have been in 2003 or early 2004, by then of course DSL had arrived and rendered such experiments (and ISDN in general) more or less pointless.