If you want to use inport/outport, the address is whatever the Windows Device Manager says it is (typically 02F8). If you're using VISA to communicate with the serial port, the VISA Resource Name is ASRL2::INSTR but typically an alias of Com2 is created for it. If you are using the old, obsolete serial functions, the ports are numbered starting at 0 so Com2 would be port 1.