ntalk
("new talk") An update of the {Unix} "{talk}" program,
old versions of "talk" being referred to as "old talk". New
talk and old talk are generally incompatible, and attempts to
get them to communicate result in entirely unhelpful error
messages.
On most modern {Unix} systems, the program "talk" is new talk,
with some {SunOS} versions being a notable and annoying
exception to this.
(1997-09-11)