Siemens 6ES7422-1FH00-0AA0 Digital Output Module — Legacy Replacement. Siemens 6ES7422-1FH00-0AA0 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, digital output SM 422, isolated 16 DO; 120/230 V AC, 2 A. The verified manufacturer lifecycle record is PM400:Announcement of product phase-out.