The Communications Tower is the primary link for off-planet communications in Doom 3. Broadcast dishes are aligned for communications directly with UAC-Earth and bridged for deep-space communications via the Phobos Routing Station uplink.
The Communications Facility also has a Maintance and Transfer area, also some airlocks that leads outside, and even a Warehouse. The Communications Transfer area also stores the mistake of Chainsaws that were delivered to Mars.
Plus the Communications Facility has two ways for Communications: The Main Communications Room, and the Satellite Control Center. The two entrances/exit that are known are: EnPro Plant and Monorail Station.