VENDING KEYS
Vending keys are classified into several vending key types as defined in IEC62055-41:
VD DK (VendingDefaultDESKey)
The VDDK is a key used to define default decoder keys and may not be used to define any other decoder key types. For further information on this key type, see IEC62055-41.
VUDK (VendingUniqueDESKey)
The VUDK is a key used to define unique decoder keys and may not be used to define any other decoder key types. For further information on this key type, see IEC62055-41.
VCDK (VendingCommonDESKey)
The VUDK is a key used to define unique decoder keys and may not be used to define any other decoder key types. For further information on this key type, see IEC62055-41.
References: IEC62055-41