Barcode symbologies supported vary by KDC.
The KDC20/100/200/250/270L/270D/350L/410/411/415/470L/470D/475S/500L support 1D barcode only.
KDC30/270C/280C/300/350C/420/421/425/450/470C/475H/500C support most major 1D and 2D barcode symbologies, and OCR.
For more detail regarding specific symbologies please navigate to the specific KDC's product page.