The Brain State Synchronizer was developed by Jim Meissner who was also active on the OpenEEG Mailing List for a while.
It’s a device that generates stereo audio pulses and Binaural Beats. The goal is to train the brain waves to follow these stimuli to induce alternate menatl states.
http://www.meissnerresearch.com/bss/index.htm
Patents:
United States Patent Number 5,135,468