Emphasis of our research lies on the application of realtime multimedia technology: tele-teaching, teleconferencing and collaborative work. To support this research we need a real-time environment that supports rapid prototyping of distributed multimedia applications. Because other systems were not suited for our purpose, or did not fit the underlying framework of operating system and network, we decided to build our own environment, rather than using an available one and changing and extending it. The resulting toolkit has the following features: network transparent multimedia services; temporal access commands for continuous media; quality of service management for all services; low level inter media and spatial synchronization; dynamic management of application topology. We found these features adequate for specifying, modeling and implementing distributed multimedia applications as is illustrated in the paper.