Importance

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Abstract

A variable message display sign comprises a plurality of interchangeable character displays each having a plurality of signal elements organized in distinct sets, with each signal element having an on state and an off state. A controller is located remotely of the character displays and produces an address signal containing character address data for identifying an addressed character display which resides at a desired address location within the message display sign. The controller also produces a set signal containing set address data for identifying an addressed set of signal elements and a data signal containing display data corresponding to desired on/off states for each signal element in the addressed set. A logic circuit is associated with each character display and has a unique character address. Each logic circuit is secured to a respective one of the character displays and has a memory operative in response to the address signal to receive and store the display data according to the set address data for an addressed set of signal elements. The logic circuit accordingly switches the signal elements of its associated character display to a desired pattern of on/off states according to the display data stored in memory, thereby to display a desired character irrespective of which one of the plurality of character displays resides at the desired address location. A data bus interconnects the controller and the logic circuits whereby the character address data, the set address data and the display data are communicated. A method is also provided for controlling a plurality of interchangeable character displays.

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First Claim