From ADC

Transfer links real-life events to relationships, which the enterprise has previously entered. The term itself implies, that there are a source and a destination. Other important attributes are a date and an amount. A notable quality of exchange-driven accumulation system is, that type of goods or services being transferred is unambiguously determined by the pair of flows. If the source produces a different resource, than the destination consumes, the transfer is invalid and will be blocked. This way the system prevents "meaningless" transactions from ever being registered.