This paper describes SCT (Sequence Charts Tool), a tool for reusing requirements in de- velopment of telecommunication applications. The tool developed under an object-oriented ap- proach supports the maintenance of reusable components and the composing of a new sys- tem from components. The tool has been used in a research work and proved to be very con- venient for system analysts to create and edit sequence charts. The paper is produced at the Department of Communication System at Lund Institute of Technology in the research project ARISE (A Reusability Infrastructure for Soft- 1 ware Engineering) which is part of the RACE programme. Keywords: reuse, object orientation, require- ment specification, CASE tool, SDL, sequence chart, telecommunication systems.