New process unit, how to initialize new unit? or should it do it on its own

Whe you install a new Process Unit (PU) it’s necessary to initialize the developer mode;
to do this, switch the printer off first. Procedure: 1. Keep both function keys pressed. 2. Switch the printer on. 3. Keep the keys pressed for at least 5 seconds 4. Switch off the printer; release the function keys. Install a new process unit with the toner container. After switching on the printer will execute the initialization procedure.

If buttons do not work – send this command to the printer
!R! TNRE ‘INST’; EXIT;