[NRL, CMU; prob. fr. the movie Tron] To
become inaccessible except via email or
talk1,
especially when one is normally available via telephone or in person.
Frequently used in the past tense, as in: Ran seems to have tronned
on us this week
or Gee, Ran, glad you were able to un-tron
yourself
. One may also speak of tron
mode; compare spod.
Note that many dialects of BASIC have a TRON/TROFF command pair that enables/disables line number tracing; this has no obvious relationship to the slang usage.