We present a scalable multiprocessor for real-time signal processing applications. The basic building block is a node with eight processors. Nodes are connected by the switch-based network Switcherland . Innovation highlights are: (a) a network with guaranteed transmission rates and bounded forwarding latencies, (b) a multiprocessor node based on RISC CPUs/DSPs and a communication infrastructure optimized for processing continuous data streams, and (c) an object-oriented programming model familiar from general-purpose systems. These properties make the described system a versatile platform for a wide range of signal processing applications.