The remote on/off feature on the module can be either negative or positive logic depending on the options. For the negative logic version, the module is turned on during an external logic low and off during a logic high. If the remote on/off feature is not used, please short the on/off pin to Vi(-). For positive logic version, the module is turned on during an external logic high and off during a logic low. If the remote on/off feature is not used, please leave the on/off pin to floating.