Abstract: A device for encoding and inputting to a computer alphabetic and topologically represented graphic data that describes, in particular, structural formulae of chemical compounds, comprising an encoding tablet, a changeable encoding form placed on the encoding tablet, a coordinate counter coupled to a computer communication line and to coordinate decoders which, in turn, are coupled to the encoding tablet, a pulse generator, a pulse distributor coupled to the pulse generator, to the coordinate decoders and to the coordinate counter, a code-pulse decoder coupled to the pulse generator and to the computer communication line, an electronic writing means which is a unique and sufficient facility exercising control over the operation of the device and including an amplifier coupled to a code-pulse decoder, a coordinate pickup coupled to the amplifier, a pressure sensor coupled to the pulse generator, a beginning-of-line symbol generator coupled to the computer communication line, and a changeable writing member whic