I am trying to figure out the main differences between tn3270 and telnet.
(FreeBSD moved tn3270 from the base to its packages collection last year.)

As far as I can tell tn3270 and telnet are the same (mostly the same
source), except for the "transcom" functionality and telnet carries across
the previous TERM setting and tn3270 (in my case) set my TERM to
ibm327-789.

Can someone please explain the usefulness of transcom and IBM 4994 style
transparent mode processing?

Is there any other differences?

What is an example of a "multiple window system" 3270 system? (What does
this mean?)

I have never logged on to a "real" IBM 3270-class mainframe (just a lot of
machines that act like it).

What is a "IBM VM/CMS"?

Is there any current purpose for the tn3270 command?

Thanks,

   Jeremy C. Reed
   http://www.reedmedia.net/