AFTER MANY TRIALS I FOUND THAT IT WILL AUTO ADD IF THE ITEM BARCODE IS SINGLE DIGIT
Well thats strange, there is no logic to exclude multi digit product codes from not adding. The key is that the barcode has to send a carriage return character at the end of the product key, which typically is a setting within the scanner to choose. Most scanner do that. Unfortuately, i do not have such an internal barcode reader to test.