Smartlink I/O, DNI required? Options

[Riley37]

The main function of a smartgun system seems straightforward. A sensor aligned with the barrel gets a target picture, a computing device does some calculations, and it sends appropriate output data to the smartgun image link so that the user's glasses/goggles display a point of aim on their field of vision, or it sends to the user's DNI so that the point of aim marker appears directly in their perceptual field of vision (along with # of ammo remaining etc.).
On another hand... where does the system get any info on where the user is looking, and thus when the direction they're looking matches with the direction of the barrel? If the system had input from a barrel-aligned sensor, and from a head-mounted sensor, it could compare the two and figure out where the barrel sensor's image corresponds with the field of vision; but it only has the former in RAW. I'm inclined to say that a smartlink can work only if it has access to the user's vision, eg their visual cortex, meaning DNI.

Is this an Awakened magical device, that only became possible in 2011?
Or am I missing something here?

RAW says that a smartgun user can eject a clip as a Free Action, without moving a finger, and can also fire without pulling the trigger. How exactly does the system get this input, if the user has an image link on goggles and no DNI? I'd say those functions are only available if the user has DNI such as trodenet or datajack.