Digital mobile communications comes to company sites. No cabling is required and the employees can be reached at any time at any place. How- ever, planning of wireless digital networks is quite different from planning traditional wire-based systems. Small, local radio transmitters (senders) have to be installed to provide the wireless devices with signals. The specifics of radio wave propagation at the installation site have to be taken into account. POPULAR is an advanced industrial prototype that allows to compute the minimal number of senders and their location given a blue-print of the building and information about the materials used for walls and ceilings. It does so by simulating the propagation of radio-waves using ray tracing and by subsequent optimization of the number of senders needed to cover the whole building. Taking advantage of state-of-the-art techniques for pro- grammable application-oriented constraint solving, POPULAR was among the first practical tools that could optimally plan cordless communication systems. In this paper, we introduce the basics of this real-life application and show how easy it is to implement the necessary constraints to solve the problem.