A data line driver is provided for driving M data lines of a matrix display such as a liquid crystal display. The driver comprises x data line circuits whose inputs are connected to a common input for receiving a serial image signal, where x is less than M. Each of the data line circuits comprises a store for storing one picture element of image data at a time, a multiplexer for storing in the store in sequence image data for m picture elements from at least part of a line of image data, where m is greater than one, and a demultiplexer for directing a line signal corresponding to the image data stored in the store to each of m of the M data lines in sequence.