1
Face William W, Katz Harold W, Miller Murray H: Two-way community antenna television system. KMS, June 6, 1972: US3668307 (166 worldwide citation)

A two-way community antenna or closed circuit television system or community cable television system which permits two-way communication (including voice communication) through a transmission center from and between various terminals, such as schools, homes, hospitals, doctor's offices, community ce ...


2