Patent US 6,788,331

An improved videofax system for displaying a video image from a digital memory, while the digital memory is being updated with data representing a new image and received from a standard telephone line or other communication channel with relatively slow data access time. A video processor circuit uses a first digital counter to increment the address of a digital memory sequentially and load the stored data to a digital-to-analog converter for display of the resulting analog composite signal on a standard monitor. The video processor uses the address provided by a second digital counter to temporarily switch the digital memory address provided by the first counter and sequentially update the digital memory with new data received from a modem, a microcontroller, or any other data storage components with slow access time, enabling a user to view the new image as it overwrites the old image with a sense of continuity between the old image and the new image.