Sourcing reality
The NX-OD6121-6: Active status means you can order it normally. No end-of-life notice, no LTB window to chase. If it's on the BOM, quote it to order and move on.
Field-fit note
Standard NX form factor – mounts on DIN rail in the NX slice. The Fujitsu connector mates with a standard ribbon-cable header; strip length and pin assignment follow the NX-series manual. If you're replacing a dead output bank and the part number matches, it's a straight swap.