The ML9204-xx is a 5 x 7 dot matrix type vacuum fluorescent display tube controller driver IC which displays characters, numerics and symbols of a maximum of 24 digits x 2 lines. Dot matrix vacuum fluorescent display tube drive signals are generated by serial data sent from a micro-controller. A display system is easily realized by internal ROM and RAM for character display. Built-in key scan for 3-channel encoder type rotary switch and 5 x 6 matrix key switch allow the user to receive each switch input.