The Emergency Operations Hologram (EOH) was a development from the Emergency Medical Hologram (EMH) and the extension Emergency Command and Conn Hologram (ECCH) concepts. It was part of the Emergency Holographic Complement of fleet carrier classes and the heavy battleship classes of Starfleet.
The EOH was developed simultaneously with the Emergency Command and Conn Hologram in 2380, after tests have shown that the Operations department of a Starfleet facility or starship could benefit from an emergency holographic program as much as a Starfleet sickbay or infirmary did with the EMH.
Essentially, the EOH was a 'backup operations officer', intended to assume responsibility for communications, sensors, environmental systems, hangar deck operations, transporter operations, sensor sweeps, and planetary reconnaissance scans in the event that the current operational crew would be incapacitated for some reason. The EOH possessed over 2 million ship operations subroutines from the operations databases of all the leading operations officers in Starfleet, and could incorporate them into its plans in the performance of its tasks.
There were five (5) EOHs in the Emergency Holographic Complement of the fleet carrier classes and the heavy battleship classes of Starfleet and of Vanguard Command. In all other starships, there is only one (1) EOH in the Emergency Holographic Complement.