Yes, everyone had high hopes for ISDN. It was a forward-thinking construct and, in fact, has been used with great success. However, I believe it's been overrun by technologies that offer more commercial opportunity. The area into which I'd been diverted by then (25 years ago) was multilevel secure voice and data comm's over ethernet, rather than telecomm networks, but I had daily contact with IP networking, which was not so widely understood back then. Ethernet wasn't so widely understood back then either. In fact, back then, "ethernet" networks provided by what was then the most popular supplier of mid-sized computers (DEC) wouldn't "talk" to "ethernet" networks from nearly all other hardware manufacturers, and required a bridge to join a larger campus-area network. Of course, then, one used a finger-thick backbone requiring two men and a boy to bend it, rather than the now-universal twisted pair.

RE