A model and a formal specification of the personal communication service obtained by the application of an object-oriented system design methodology is presented and described using the executable object-oriented specification language Mondel. The goal of developing a specification of PCS is primarily to introduce some structure and formalism in its description, which has so far been done informally, and also to provide a better understanding of its constituent elements and their interrelationships. As Mondel is an executable specification language, simulation is used to verify the basic functionality defined in this specification of PCs. Simulation using various scenarios also provides a means of presenting the different concepts of PCS.>