This chapter provides information for the 4-Port VNA Response menus for configuration of the required S-Parameter or user-definition of a unique parameter. The MIXED-MODE dialog boxes described below allow mixed-mode response setup on a trace-by-trace basis with multiple response options for each trace. This menu also controls the rear panel External Analog Input port source. For information on the Response menus for 2-Port VNAs, consult Response Menus - 2-Port VNAs