When equipped with Option 77, the Vector Network Analyzer is able to leverage both of its test ports in order to measure the S-parameters of balanced and differential test configurations. Using mathematical transformations, the Vector Network Analyzer can convert single‑ended S‑Parameters into the equivalent balanced differential, common, and mixed mode S‑parameters: Sd1d1, Sc1c1, Sc1d1, Sd1c1. This approach provides accurate results for passive measurements. Note that the Vector Network Analyzer is not simultaneously transmitting from both Port 1 and Port 2 during this measurement. This measurement can be used as an alternative to a sampling oscilloscope for verifying performance and discontinuities in differential cables.