2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/33230This paper describes a case study conducted in collaboration with Nortel to demonstrate the feasibility of applying formal modeling techniques to telecommunication systems. A formal description language, SDL, was chosen by our qualitative CASE tool evaluation to model a multimedia-messaging system described by an 80-page natural language specification. Our model was used to identify errors in the software requirements document and to derive test suites, shadowing the existing development process and keeping track of a variety of productivity data.18 pages, 5 figures, to appear in Proceedings of FM'99: World Congress on Formal Methods, September 1999Software EngineeringF.3.1;K.6.3;D.2.7;D.2.5;D.2.1;C.3;D.2.4text