tl1

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

TL1

   Transaction Language 1.

   A subset of {ITU-T}'s {MML} from {Bellcore}, with simpler
   syntax.  TL1 is similar to {USL}.  It is used in
   communications between telephone operating systems and remote
   network test equipment.

   [OTGR, TR-TSY-000439, section 12, Bellcore].

   (1994-12-14)