Pioneering PC based workstation simulation, Intusoft introduced its original IsSpice simulator in 1985. Now, several generations of simulation technology later, the 4th generation IsSpice4 simulator combines Berkeley SPICE 3 (Simulation Program with Integrated Circuit Emphasis) analog simulation with the Georgia Tech XSPICE event simulator for a native mixed-signal simulation capability. Added to both of these technologies is an interactive capability that lets you make parameter modifications and watch the simulation results instantly. (Detailed IsSpice4-Berkeley SPICE Differences) The IsSpice4 simulator uses the Microsoft ActiveX technology to provide an automation interface so that the simulator can be controlled using external scripts as well as the internal scripts implemented in Berkeley SPICE3. Intusoft is the only commercial SPICE vendor that implements and extends the Berkeley script language introduced with SPICE3. This important feature allows IsSpice4 to make and record sophisticated measurements of circuit performance; for example, rise time, gain margin or propagation delay. These automatic measurements are set up and made available to the user through the SpiceNet schematic package. The IsSpice4 specification describes the analysis types and built in models that IsSpice uses. A feature summary is also available.