Symbol LS-2100U User Manual page 22

Code Option
EAN 8 Convert to EAN-13
On
When this option is selected the scanner will
convert EAN-8 to EAN-13 by transmitting five
zeroes after three characters.
When this option is selected the canner will
convert EAN-8 to EAN-13 by transmitting five
zeroes before the barcode
UPC-E Convert to UPC-A
On
End Configuration
<Off>
<Off>
22