Cortex Stealth Mode

Cortex Silent Mode allows the user to turn off AIS transmissions while monitoring other vessels. Silent Mode has a coined name, "Stealth Mode." It is a popular feature on Ocean Racing boats when it's advantageous to be invisible to their competitors yet still see shipping movements and continue to use collision alerts for safety. 
Cortex Stealth mode also inhibits the DSC system from sending position reports when requested by another DSC system, commonly known as buddy tracking. Cortex Stealth mode control can also be wired into the GPIO port and controlled with a switch. 
 
To use the Stealth mode on your Cortex handset or on the Cortex Onboard app, tap the Transponder icon. 

Tick the Stealth mode switch green shows it is active, and TX is not transmitting.
 

The status report confirms the Stealth mode off is also orange on that same view.