ReWire

An inter-application communication engine developed by Steinberg that allows MIDI and audio applications to interact and cooperate with one another. For example, the audio output of an application may be routed to the audio engine of another and output with the second application’s audio. Further, they may communicate with each other via MIDI so that one can control the other or so they can be synchronized. ReWire currently works with just about every DAW application such as Pro Tools, Digital Performer, Logic, Sonar, Cubase and others.