To harmonize with NMRA’s “RP 9.2.3” programming RP, the DH140 and subsequent decoders do not implement the “legacy” {F9} decoder interrogate instruction. Note that this will not allow correct “address” read back on Marklin 6032 and older revision Lenz programmers that use this older {F9} instruction, and not physical register 1 read back. Note that even though the read back will fail with no confirmation, you will always be able to write a new value correctly.