The Otto Passive Mono is a completely passive module.
It has 8 mono jacks on the front and a pin-strip on the back with access to all jack signals.
For each jack you will find pins for the main signal and a break/normalization signal.
Each mono jack has a break- or normalization-function. When no connector is inserted in the jack on the front, the main-jack-signal is also sent out to the break/normalization pin. But if a connector is inserted, nothing is sent out on the break/normalization pin.
The GND for all jacks and pins are connected to the same ground-plane. That ground-plane is also connected to the front and the jack screws. When you install the module in your rack, it will also be grounded to your rack.
The module can be used in many use-cases where you need mono-jacks with the connections freely accessible at the back.