A TDT Switch Module J. S. Pezaris Computation and Neural Systems California Institute of Technology, Pasadena, CA 91125, U.S.A. Abstract The design and construction of a switching module for use with Tucker-Davis Technologies equipment is presented. This four-pole-double-throw (4PDT) module is used, for example, to periodically switch between a recorded voltage and a reference voltage during neural recordings to mark the time of external behavioral events. Fetch PDF of paper John Pezaris, Caltech, Mail Code 216-76, Pasadena, CA 91125, pz (at) vis (dot) caltech (dot) edu, 15 Feburary 2000.