Abstract: Apparatus for controlling a formerly passive-display television infrastructure, such as in a single-location commercial establishment, includes a text and graphical information input interface which uploads the text and graphical information, and the control information for its display, to dedicated control modules connected to each television. The apparatus can provide an addressable or a direct-wired ability for the operator to display text and graphics overlaid on an existing television channel at the operator's choice of time, text, and location on the screen. Alternate video source inputs may further be controlled to replace the currently displayed television channel for a selected amount of time.

Abstract: A technique for determining and resetting one or more flags in a digital word in memory in which the flags comprise added bits in known locations different from any of the magnitude bits in the word. A sign bit is included and a flag is set by making its bit value differ from that of the sign bit. A digital word from the memory is AND'd with a bit mask to check the flag bit location. A parity routine is run to determine whether the flag bit is set, and if so, the memory location of the word and the type of flag is recorded. The word with the flag bit set is XOR'd with another bit mask to reset the flag bit so that the word may be returned to its memory location with the flag reset.