“Apple Notification Center Service with an External Display The Apple Notification Center Service (ANCS) function in iOS is the source of notifications displayed as a banner message along the top of the active screen (or in place of the entire active screen) for timely alerts (e.g., when you receive a text message, miss a call, or for a variety of other applications). For example, when you receive an incoming call, the ANCS temporarily replaces the active screen with the screen shown in Figure 9-5”