From my notes:-

Quote:

The measurement data from the Pressure and Flow Modules is sent to the System Controller via the Module Interface Bus in the form of a variable frequency square wave in the range of approximately 1,500 to 9,500 Hz.

The System Controller PCB assembly digitizes this information so it can be processed, linearized per the EPROM data and displayed via the Keyboard-Display PCB assembly.


If you don't inspect ... don't expect.