This is the "brain." It houses the LCD display, keypad, power supply, and the microprocessor. The manual stresses that the central unit is usually located in the Engine Control Room (ECR).
This requires the official service code – usually not disclosed to ships’ crew to prevent tampering. However, the manual details the principle: deckma omd11 manual
If you are a Chief Engineer, the physical binder should be in the ship’s library. However, in a digital age, the Deckma OMD-11 manual PDF is the most searched document. Here is where to find it legally: This is the "brain
Warning to the reader: Do not use a generic manual from the internet unless the revision number matches your hardware (Rev. 4.2 versus Rev. 5.0 have different service menus). Warning to the reader: Do not use a