(covers information from Warship Voyager)
The Command Core Hologram system is used as the command linked holographic avatar between the ships main computer and its crew. This series of hologram is far more advanced than the Emergency Command and Conn Hologram because of its ability to control all ships functions, not only in emergency situations, but at all times (if necessary). The Command Core Hologram usually takes the role of first officer, or in some situation the EXO.
To act as a physical representaion of the Main Computer, allowing the crew to interface with the Computer in all aspects of its primary and specialized control functions. Also to act as a fully functioning member of the ships command crew being given orders and performing tasks far dangerous for any of the organic crew members to perform themselves, yet can be still performed just as efficiently as if if it were done by one of the human crew themselves.
The Command Hologram is linked to all the ship's systems with seemingly telepathic command, controlling everything from gravity control to Life Support Systems.
The average Command Core Hologram is capable of providing enough power from its own internal Holo Emitter that it can power an entire small army of Runabout-class Fighter Shuttles or 1 Battle Cruiser for a year if necessary.
Many Command Holograms have basic personality programming which is largely defined by their function. However, there are some Command Holograms that display some individuality, such as Voyager 1, however, most Holograms stick to most of their base programming.