3-4 years prior to RoboBoard was a system called FirstClass (originally macintosh only) that was started to be a groupware 'learning management system' but was heavily utilized as BBS software as well.
It provided email and forums (even with fidonet support, although mainly via 3rd party software as FCs remained pretty lacking), voice/fax, file transfer, etc and the protocol was multithreaded so you could be doing all of those things at the same time, and all over a 1200 baud modem.
It was primary used with a GUI client, although had options in the server to provide a crappy text interface for dialup users in a terminal app. This text interface had nothing on wwiv but did at least provide a simple way to download the mac or windows GUI client for the advanced features.
They later added appletalk networking and finally tcp/ip as well in the early 90s, but by 94/95 the BBS era was pretty well dead and everyone moved on to the Internet.
At least around these parts the transition was a fairly obvious one.
First you offered a BBS.
Then you offered a BBS with Internet.
Then you offered Internet with a BBS.
Finally you just offered Internet.
Between Eternal September in '93 and the web just being invented shortly before, that is when Internet usage exploded and was the beginning of the end for the entire BBS world.