If you do have the following errors on your sales screen when setting-up the Serial Cash drawer:
Please go to your control panel and the printers and devices.
Right click on the screen and open device Manager.
The following will pop-up.
Please open Ports(COM & LPT)
Right click on COM1 or COM2 (Normally a physical COM Port will be either COM1, COM2 or COM3)
The following will open.
Please go to your POS.
On the POS open Maintenance - Setup - Program options.
Go to Hardware - Cash Drawer
Add the setting shown above, under your Port setting.
Save and test the cash drawer when you do a sale it should open now.