The agilent 35677A is a 100 kHz to 200 MHz scattering parameter test s that works with the 3577A network analyzer. Alth This test set provides a convenient method for making reflection and transmission measurements of one- and two-port devices. The 3577A provides signal, power, and control for the test set and provides a menu that includes S-parameter softkey selections in S11, S21, S12, and S22. These are defined in terms of receiver inputs and test set direction. Changing the test set direction effectively switches the signal source and termination of the device under test as though it were removed and reconnected to the test set in the reverse direction. Different S-parameters may be selected for each of the two traces.