This paper describes a method for interpretation of lines in distributing frame drawings of a telephone company. The lines are composed of hierarchical components: intersections, segments and line links. First, intersections are located. Segments of lines are then detected. Adjacent segments are finally linked into a line. A postprocessing step refines the lines. The line extraction and classification are insensitive to touching characters and broken lines. A number of experimental results using real drawings demonstrate good performance of the algorithms.