The Overhead panel has been build as a separate stand-alone program.
It is used to control and monitor the aircraft systems. All the subpanels are inplemented (Fire, Hyd, Fuel, Elec, Air Cond, Flt Ctl, Gpws, Cargo, … ) as well as the ADIRS subpanel.
It runs on a PC and communicates over the network with the central simulator core engine.
This software based overhead panel simulation is used for testing, or when the A320 Simulator Software is used stand-alone without a Hardware Cockpit.
In the A320 Simulator we are using the real original Airbus overhead subpanels which are being interfaced to the A320 Simulator Software core engine.