Millimeter wave frequencies were traditionally dedicated to military applications with some commercial use for point to point microwave links. Sub-octave bandwidth waveguide was the preferred transmission line as millimeter wave capable coax cable and connectors were not available. All that has changed in the past decade with technology improvements in semiconductors, components, cable, and connectors. It is now possible to use millimeter wave frequencies for commercial / consumer electronics. This white paper will discuss issues of transferring millimeter wave signals through coax cable within a test system and the benefits of improved measurement accuracy by reducing the size of the test equipment and using fewer interconnections.