DDC is the recommended Daily Duty Cycle of scans for a scanner by the Manufacturer. NETWORK DOCUMENT SCANNERS: Scan Station 710 network scanner 70/140 IPM $ 1979 : These models ONLY attach DIRECTLY to a NETWORK: Fujitsu N7100 network scanner 25/50 IPM $ 1427: Canon SF 400 network scanner 4 5/90 IPM $1579: HP Scanjet P ro 4500 fn1 network scanner 30/60 IPM $ 789