C19 to C20 compatibility

Yes: C19 is made to mate with C20. That is the jumper for a C20 PSU inlet and a C19 PDU outlet.

No: C19 does not belong in a C14 inlet. No: a C13–C14 cord is not a substitute for this pair.

NVIDIA qualifies locking C19/C20 cords at 250 VAC, 20 A, 1200 mm for DGX H100/H200, B200 and B300 AC. Use the NVIDIA cord or an equivalent locking C19/C20 that meets that rating.

Related: C19 vs C20, C19 C20 server power cord.