The system needs these 3 things to work:
1. Smartgun system.
2. Smartlink.
3. A means to connect the two.
The Smartgun collects the data, sends it out through the connection, then the Smartlink displays the data in your field of vision.
1. The Smartgun is the transmitting end of the system, and can be installed externally or internally on a firearm or projectile weapon. It has all the whizz-bang features as detailed on p. 433 of the CRB.
2. The Smartlink is the recieving end of the system. Without it, the Smartgun is just transmitting data without a means to view it, and no way to access it's features. It is detailed on p. 444 of the CRB. It can be an enhancement to an imaging device, implanted directly into your eyes, or as a part of a Cubereye system.
3. To connect the system you can use a cable or wirelessly in conjunction with a DNI. The cable can be connected to the imaging device that the Smartlink is installed on, or directly into your nervous system through the connection of a DNI.
How you can mentally control the device with a cable connected to just some glasses is beyond me, though. Eye movement, perhaps?