I am not sure that they even refer to the same things. X.25 is the ISO
(International Standards Organization) standard for Level II (I think)
interfacing. ISO members include CCIT ,ANSI, IEEE and others. What is
important is that X.25 is being used for the new work on digital networks
by the 'big boys' for national and international packet switching networks.
These guys are working with coast to coast megabaud links and anticipate
that such things will be common place for the average users within a few
years. While I am sure that eventually that will happen, I also suspect
that those closest are a little optimistic.
Bill, Telenet, Tymnet (and Itapac for italians like me..:-) are ALL X.25
nets. You can call them via a X.28/9 interface (= 3/12/24 modem on dial-up
line), or via an X.25 interface (= 24,48,96,192 terminal on a special
leased line). – Mario