The 961 was designed for use with the 960 Sequential Controller. The module was available in two versions, the "P" and "C" type. The illustrated module is the "P" type unit for inclusion with portable systems and is not the same height as standard 9 series modules, but the same size as "console panels". The "C" type panel features the Audio to V-Trigger section positioned at the top, followed by two S Triggers to V triggers the two V Trigger to S trigger sections.