During a battle, HMS Belfast's 6" main armament would be fed infromation from this Director Control Tower (DCT), which would track all the available targets, estimate their range, and compute the angle of elevation and powder charge for attack. This information would be passed down to the Operations Room, which would track all tragets and decide which was the priority to fire at; and the magazine, which would send the gun loaders the correct amount of powder; while the gunners loaded the shells (either high explosive for land targets or armor piercing for ships) and set the fuses. The fire control officer, not the captain, would actually fire the guns. All of HMS Belfast's 6" guns could be directed from either of her DCTs.
This 6" DCT had Type 274 tracking radar with a range of 16 nautical miles (11,000 meters).