The Salvage Computer is a computer that is required for operating Salvage Weapons ; which mine solid blocks and add them to your inventory in exchange for power.

To connect the salvage cannons to the salvage computer, select the computer by pressing C (default) while aiming at the computer.  Any salvage cannons placed while the computer is selected will be controlled by that computer, and can be assigned to the quickbar.  Alternatively, placed cannons can be linked to a computer by selecting the computer, then aiming at the cannon blocks and pressing V (default).  This method applies to all other module-upgrade sets, such as anitmatter cannons, missiles, docking modules, etc.