If you are currently using RCA or Red, white and yellow connection for your setup and are trying to connect the TVGuardian LT, you will most likely need to use the small Yellow composite cable splitter that came with the TVGuardian.
Attach the composite splitter to the back of your cable/satellite box or DVD player's video output, this way you can send 1 composite cable to the TV for picture and another to the TVGuardian for filter.