The touch panel man-machine interface system was developed at SLAC to help implement control room consolidation. The decision to consolidate the two accelerator-research area control rooms was made in 1970 in order to increase operating efficiency. 1 An acoustical touch-panel was proposed and developed. 2 A cross-wire touch panel was implemented when it appeared that it could be produced more quickly and at a lower cost. We now have eight cross-wire systems and one acoustic system installed as control surfaces in our Main Control Center. These control surfaces are mounted over standard C.R.T. video monitors to form the control-display unit. We chose this method of control and display over competing systems such as light-penunits because of the ease of control. Lightpens become a burden when several displays are mounted side-by-side. The operator is required to make many changes on all three units of a group and the use of lightpens would be too time consuming. ’