Up to 9216 fast discriminators are required for processing signals of the Fermilab silicon strip detector preamplifiers in experiment E789. These discriminators were organized in 75 identical 128-channel subsystems. The authors describe the design considerations of the system and its performance, based on several months of testing the completed system. The 128-channel module had four 32-channel discriminator boards, eight 16-channel line driver boards, and a signal-routing motherboard. The 16-channel line driver boards transfer events from the motherboard through cables to the remote processing electronics. Three subsystems fit into the frame of a standard CAMAC crate.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>