(1) (Transparent Network Transport) Services from the telephone companies and common carriers that provide Ethernet and Token Ring transmission over MANs and WANs.

(2) An earlier name for a DOS extender program from Phar Lap Software that ran on top of DOS and allowed DOS applications to use various Win32 features, including memory allocation, DLLs and threads. VenturCom, Inc., Waltham, MA bought Phar Lap in 2000; the company renamed itself Ardence in 2004, and Citrix acquired Ardence in 2007.