3.2 F RONT P ANEL DSP I NTERFACE Fig 3.3 shows the user interface section of the front panel. Fig 3.3 HCU Controls To switch the unscrambler on, push the black push-button switch on the front panel. The user interface LCD will illuminate once the unit has been powered on. The user interface Liquid Crystal Display (LCD) shows parameters used by the unscrambling algorithm and allows adjustments of these parameters to the users preference. The keypad is used to scroll through and set the chosen parameters. For detailed information on the user interface see section The depth pot is the main control for the helium unscrambling function and this alone can be used to set the unscrambler parameters to match the depth and gas mix of any given divers. The depth pot varies over a range of m to 500m.