What is a good way to look at the performance of a transmission line in Spice?

I have a model exported from Sonnet to PSpice. I would like to see the "real" loss associated with that transmission line pi-model.

For an example I would like to use some random FPGA I/O line. If the Voltage is X then what is Y out.

Should I place a step voltage in and see what the voltage out would be? If it is a, or suppose to be a 50 Ohm Line, should I terminate it with 50 Ohm and see what that output is with that step input? This would also give me the rise time associated with the line as well correct?

Thank you.