AuDSim Basic - Windows based audiometer simulation software emulates a diagnostic audiometer for unmasked pure tone air and bone conduction testing. Three modes of operation allow self-paced instruction. Handholding mode guides the first time student in the proper technique for obtaining threshold. Practice mode allows unlimited trials of simulated patients with slight variances in the simulation. Test mode eliminates all coaching, and documents the results of the student's threshold evaluations vs. actual thresholds. AuDSim Plus extends the basic module to provide masking simulation, with diagrams to illustrate masking effects as the student adjusts test parameters.