A:Answer Thank you for reaching out. First check out the letters at the end of the LaserJet model numbers. FDW means Fax, Duplex (double-sided printing), and wireless. The FNW is Fax, Networking (ethernet) and Wireless. Besides those differences the 400 series LaserJets are considered the next model up. You get larger toner cartridges (lower cost per page), single pass double-sided scanning, slightly faster print speeds and a few other minor differences.
