If you want to check if a specific Port is used by the XCOM server running on z/OS you can use a quick and easy command from the ISPF Command Shell:
NETSTAT ALLCONN (PORT nnnn
The output of the command is as follows if the specified Port is in use:
MVS TCP/IP NETSTAT CS V2R3 User Id Conn State ------- ---- ----- XCOM 0000004D Listen Local Socket: 0.0.0.0..8044 Foreign Socket: 0.0.0.0..0 ***
Here we see that XCOM is listening on Port 8044 (by the way, that port is the default Port for XCOM).
The output of the command is as follows if the specified Port is not in use at all:
MVS TCP/IP NETSTAT CS V2R3User Id Conn State ------- ---- ----- ***