A system for driving an electric handpiece in response to a pneumatic control signal may provide for fast interchange of handpieces, self-calibration and wide dynamic range of operation with precise speed control. The system may be incorporated into virtually any dental treatment center using traditional pneumatic drive handpieces, and a conversion kit may facilitate such conversion. The system may provide not only for controlling the speed and torque of a tool coupled to an electric drive handpiece responsive to a pneumatic control signal, it may also provide for coupling cooling air and treatment media, such as air and/or water to the handpiece. Coupling of a handpiece to an operating base of the system, including coupling of media lines and electrical connections may be made with a simple press and twist action using quick connection structure.