DME is Data Medium Exchange, its a ten digit long reference number generated when a payment run is created. If I am not wrong a DME reference number is created for a total of payments for each payment method. All the payment documents created for each payment method can be tracked under this reference. DME is stored in the table REGUT. This can be used for the automatic bank reconciliation too but it should be made sure that this DME is sent and received in the interface files to the bank.