Abstract: A panelist response scanning system includes a plurality of product scanning units for location at respective stores, a targetable television system, a plurality of panelist identification means for identifying respective panelists, and a central processor for coupling to said product scanning units. The targetable television system head end transmits normal and substitute television program signals and signal substitution control signals to a plurality of panelist receiving stations. The control signals include panelist address signals corresponding to respective panelist identification means. Each panelist receiving station selectively substitutes substitute program signals in lieu of normal television program signals upon receipt of a respective panelist address signal. The product scanning units receive panelist identification from a purchaser of products from the respective store and receive product identification corresponding to such products and produce signals indicating the panelist and the product.

Abstract: A signal substitution system for cable television applies substitute television program signals in at least one substitute channel to the transmission cable along with singal substitution control signals. The signal substitution control signals include a plurality of different terminal command signals and a plurality of different event command signals, each of the terminal command signals including a respective panelist address signal for identifying a respective panelist receiving station, and each of the event command signals including a normal channel identification signal for identifying a normal channel into which a substitute television program is to be switched. A controller at each panelist receiving station responds to the signal substitution control signals by selectively switching a substitute television program into a normal channel.