Scan barcodes on computer monitor

We just discovered the potential joy of entering gift data via a barcode scanner. However, our gifts are sent to a bank for deposit, the bank scans the checks and the mail piece that would contain the RE generated barcode, then emails those scanned documents back to us. Therefore we need a barcode scanner that is capable of scanning those barcodes off of the computer monitor. My currant understanding is that I need a CCD scanner - and I bought one to test. However, I can't get it to scan off the screen. I don't know if this is a monitor setting I need to change, or a set up in the scanner - or if I need a different type of scanner. I also need to to know about "keyboard wedge" and whether or i not I need to install software for this. I have gotten conflicting, yet completely vague information regarding the "keyboard wedge". So if you are currently using this technology and would like to share some 'how-to' I would be most grateful. Rosemary H. NH-CC New Hampshire