Virtual com setup
1. Install Prolific PL2303 driver
2. Install STEP-5e utility (v1.2.2.10 or newer)
3. Go to utility --> Advanced Settings--> USB Port Setting--> select Virtual serial port
4. A com port will be auto assigned. If a different port is needed, go to Device Manager, 
select properties of Prolific USB to serial --> Port settings tab--> Advanced button--> select COM port desired then click ok. 

