http://www.rme-audio.de/products/fireface_400.php
Left hand: handbook link
https://archiv.rme-audio.de/download/fface400_e.pdf
Its all explained in the handbook chapter ...
20. Stand-alone Operation The Fireface 400 has an internal memory to permanently store all configuration data. These are:
Settings dialog
Sample rate, clock mode Master/Slave, configuration of the channels and the digital I/Os.
TotalMix
The complete mixer state.
The Fireface loads those settings directly after power-on. A simple, yet useful application is to store the correct clock mode, avoiding wrong clocking and noise disturbances in a complex setup, caused by wrong synchronization. Usually the unit will be configured by the Windows or Mac driver, so for the time between power-on of the computer up to the loading of the driver its state might be wrong.
This total configuration feature in stand-alone operation - without any connected computer - turns the Fireface into lots of dedicated devices, see examples in chapter 20.2 up to 20.6. Furthermore TotalMix (and with this all examples) can be MIDI controlled even in stand-alone operation, see chapter 28.8, Stand-Alone MIDI Control.
In stand-alone mode, the encoder knob can operate like a MIDI controller, sending Mackie control compatible MIDI notes to the Fireface's MIDI output. To activate this mode first activate MIDI control in TotalMix (Enable MIDI control), then transfer this state via Flash current mixer state into the unit. Turning this mode off is done in the same way, but with MIDI control deactivated.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14