Ports are required to be in sequential order with no numbers missing. If the ports are not in sequential order, you will receive an error message when you attempt an analysis. If you are editing your circuit in the project editor, you may renumber all of the ports in your circuit to ensure that they are sequential on the Ports page of the Circuit Settings dialog box. The port order for the S, Y, or Z-parameters will be listed in increasing numeric order. For the example of a two-port, the output would be S11, S21, S12, and S22. For a four-port, it would be S11, S12, S13, S14, S21, S22, etc.
If you have deleted some ports such that your ports are no longer sequentially numbered, you may automatically renumber all of your ports. Duplicate port numbers can be changed or kept. If you wish to renumber your ports, proceed as follows: