1. A television communications system for transmitting data signals on a frequency channel from a headend station to a plurality of user stations comprising: data means for generating data signals at said headend station; control means for generating a control signal at said headend station; video format means for generating video line timing signals at said headend station; first headend processing means in communication with said data means and said video format means for combining said data signals with said video line timing signals to generate full-field data signals in video line format for transmission to said user stations, each line of said full-field data signals in video line format corresponding to one or more individual pages of data for viewing; second headend processing means in communication with said control means and said first headend processing means for injecting said control signal in a vertical interval of said full-field data signals in video line format; transmitting means in communication with said second headend processing means for transmitting said full-field data signals in video line format injected with said control signal to said user stations; receiver means at each of said user stations for selectively receiving said full-field data signals in video line format injected with said control signal; extractor means connected to said receiver means for removing said control signal from the vertical interval of said full-field data signals in video format injected with said control signal; text and/or graphics generator means at each user station connected to said receiver means for generating text and/or graphics data from said data signals; and logic means for activating said text and/or graphics generator means in response to said control signal.