T bombs are simply small mines that can be delivered through a Transporter, or pushed out of a Shuttle Bay. As opposed to the Nuclear Space Mines that can only be pushed out of the Shuttle Bay. They are in SFC3 but only deployable through the Shuttle Bay.
ADD6 and ADD12 is the point defense system used by Klingons, Federation and Kzinti. It engages Drones and Fighters (not PFs) the only difference between the two is the number of shots they can fire before being reloaded, the ADD6 has 6 shots, the ADD12 has 12 shots, both types of ADDs carry two full "racks" of reloads. Unlike the Pla-D the ADD has a % chance to hit. If it hits, it completely destroys a drone (again unlike the Pla-D if a large drone can get far enough away the Pla-D may not do enough damage to destroy it) And it does (IIRC) 1-3 damage to fighters.