Siemens 6ES7422-1FF00-0AA0 Digital Output Module — Legacy Replacement. Siemens 6ES7422-1FF00-0AA0 is the exact manufacturer order number for a digital output module in the SIMATIC S7-400 portfolio. Siemens describes this exact reference as: SIMATIC S7-400, SM 422 DIGITAL OUTPUT MODULE, OPTIC. ISOLATED, 8 DO, 120/230V AC, 5A. The verified manufacturer lifecycle record is PM500:Discontinued Product or end of PLM & Support.