This model shows a transmission line model and bi-directional test bridge. Reflected and transmitted signals are slightly different if the test direction is changed. This is because the line model is not symmetric. This type of model can be used both to explore the impact of cable choice on transmission characteristics, and also to compare relative fidelity of different transmission line model structures and parameterizations.
As the line model is linear, a frequency response can be obtained by linearizing the model. If you have Simulink® Control Design™ installed, then you can do this by selecting Analysis->Control Design-> Linear Analysis to open the Linear Analysis Tool. Change the Plot Result to New Bode, and then click on Linearize.
For a more detailed example on how Simulink® Control Design™ can be used with SimElectronics® models, see the JFET Amplifier and Frequency Response Analysis example (model file elec_jfet_amplifier).