Happily, there are braindumps out there, which is enough to make one's way through the Billy's woods. Thanks a lot to Robert and all the contributors. Let's all keep the site up and running. Both quite informative, especially the latter. No network connection.
Answers are accordingly wrong transceiver, loose cable, frame type.
Know what they are and the answer is plain simple. Got a question on X.25 - reliable communication through unreliable switched network. Win95 NTWS NTS 11. Got the question involving a company having 72 locations all over the world with 50-100 PCs at each site. Everywhere there are Win3.11 and Win95 client computers among PCs running other OSes.