Below are the steps to find out what Com Port Windows has set for your USB serial cable.
1. Connect the USB serial cable to the laptop
2. Windows will allocate a Com Port number to the USB serial cable you have just plugged into the PC. You can find this out by opening device manager ('How to' link here) and looking at the connected ports as below:
Note: Windows allocates Com Ports to USB Serial cables when they are plugged in. If you unplug and reconnect the cable you may have to check the Com Port using step 2 and change the settings in TCS again.