Research and development projects at the AT&T (American Telephone and Telegraph Company) National Teletraining Center (NTC) are geared toward increasing understanding of the various psychological, sociological, ergonomic, and environmental factors involved in teletraining, and toward improving the ability to manage the distance learning environment effectively. This paper presents a retrospective look at five years of learning from teletraining, with an emphasis on student learning outcomes and on what distance educators have learned about the design and management of teletraining systems. Included are: (1) a description of teletraining and research projects at the NTC; (2) a definition of teletraining; (3) a discussion of the instructional effectiveness of the medium, including reviews of studies on students' achievement outcomes, acceptance of teletraining, and expectations; (4) a cost-benefit analysis of the medium; (5) an outline of course and curriculum development activities of the NTC; (6) a list of instructor competencies required for teletraining; (7) descriptions of media attributes; and (8) system implementation guidelines. Future research directions are discussed. (27 references) (GL)