a handpiece connector cooperates with the logic control circuit in an ultrasonic surgical system to distinguish types of handpieces , to indicate types of handpieces , to control differing operating frequencies for such differing handpieces , and to provide logic signals for controlling other system parameters dependent on the type of handpiece selected . a handpiece connector is prewired in a manner which is electrically indicative of one of several parameters to identify the selective handpiece . a logic control circuit , when connected to the handpiece , indicates that a handpiece is connected , indicates the type of handpiece so connected , indicates and controls the frequency of operation pertinent to that handpiece , and controls other system operating parameters related to the selected handpiece .