Seems we have (2) licenses of this (DxSim I/F Op SW) and I unfortunately do NOT know what this is. But, what I do know is that if more than 2 EE's are attempting to open DxDesigner a gui pops up stating that it can't find license feature for it but you can eventually open DxDesigner.
DxSim is the predecessor to Hyperlynx Analog. You should be able to review the license feature at this link:
Contact Support or your Account Manager for more information.