In recent years there has been considerable discussion of Bi-Directional CATV systems. Most of these discussions have directed themselves to a particular approach and spent most of the time enumerating the information and services that could be carried by the system.
I have spent considerable time in analyzing the various methods of providing Bi-Directional Transmission. The two techniques which become obvious are Dual Cable and Single Cable with diplexing filters. The techniques are not new or revolutionary, but simply show that today's system owner can build a good quality two-way system at minimal cost.