The system provides means for the automatic detection, extraction and digital encoding of the search plot data available from 2-dimensional radar equipments. Conversion from polar to Cartesian co-ordinates is effected, and the encoded Cartesian plot data are transmitted for remote use over long distances using a single telephone circuit. Full radar accuracy, resolution and data are maintained. The local or remote coded plot data are suitable for decoding and display or for direct insertion into a digital computer programmed for filtering, plot correlations into tracks, etc.