e04de9a7_cess_ATM___Hyosung_Error_Codes__Resolution
[Code] 20001 [Description] Unable to detect a cassette [Resolution] 
Remove and replace cassette – Check the micro-switch located on the inside left wall of the dispenser. Adjust the micro-switch if needed, also check the white plastic clips that hold the cassette in place. If they are broken the cassette will not stay in the dispenser.
Access ATM » Hyosung Error Codes