I believe that "PC-DMIS" is a proprietary CMM software package sold by Brown & Sharpe, whereas DMIS stands for Dimensional Measurement Interchange Specification, a "universal" CMM-CAD language first developed by CAM-I in the late '80's. DMIS was/is intended to be made available at no charge to any CMM or CAD manufacturer, as an attempt to standardize the interchange of data between CMMs and CAD systems. PC-DMIS, on the other hand, is a software system that uses many of the features of DMIS, but is not free.