S-parameter port detection

Hi Everyone .
I have a very basic question.

I have a 4 port s- parameter file in touchstone format.
I don`t know which are the input ports and which are output ports.
Can we detect it by looking at the s-parameter file? I need to connect it with 2 buffers.

draw a simple schematic in ADS and connect two terminals to an s2p data item and give your s2p file to that item, then run an S-parameter simulation to see the results.

now you can see which is s11 or s22

What is the S-Parameters for ? An Active or Passive device ?
One thing you can do is see which ports have the biggest values. Those would
most likely be the gain ports or throughput terminals.

If S34 has the biggest numbers then Port4 is like an input and Port3 is the output...

i.e. If it is like a 3-way Splitter then S21, S31, & S41 should be close to the same values.