VTAM

from The Free On-line Dictionary of Computing (8 July 2008)

Virtual Telecommunications Access Method
VTAM

   (VTAM) A data communications access method compatible with
   {IBM}'s {Systems Network Architecture}.

   [More detail?]

   (1995-01-30)

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

VTAM
       Virtual Telecommunications Access Method (IBM, SNA)