COM Port Settings
Make sure the COM Port settings are correct. If you connect your scanner via the cable through your computer's COM1, then make sure the software is set to COM1 (COM2 > COM 2, etc.). Check the cable and make sure it is securely plugged in to both sides (computer and scanner), as well. Make sure the scanner is powered and turned on.
This is the most common reason for computer communications errors.
If the problem still continues, you may need to check your Windows settings for the COM PORT, under Device Manager/Ports (Com and LPT). If you see a exclamation mark in a yellow circle or a red X, then there is an issue that needs to be resolved with your computer and/or Windows operating system. Of course, this is if you are using Windows on a PC.