question

We need to generate or have access to a unique transaction number for all payment transactions within a fleet of vehicles using multiple clover Flex terminals. Can someone explain the logic behind the Transaction # that is presently generated and exported from transaction payments. It is obviously a unique serialized counter specific to each terminal. How is the start number for each terminal determined or calculated? Do these numbers have an upper limit? Can this counter be controlled or reset? If not natively available, we are potentially looking at using these existing numbers combined with a serialized date to create overall unique numbers. Any feedback or thoughts on this would be greatly appreciated. Thank you,