EOC - Emergency Operations Centre. Used to be known as CAC (Command and Control) but went all modern on us a few years ago.
This is the large control room from where every ambulance in London is monitored, directed and supported. It is based at the LAS Waterloo HQ and works like this:
A 999 call is received and passed on to the relevant Sector desk (I work in Central Sector). The nearest ambulance is assigned to the call and information relevant to the call is updated. Cancellations are sent from here. The police and other support emergency services can be activated from here. For example, the Helicopter Emergency Service (HEMS) is activated from a single desk at EOC.
Calls may also be 'filtered' by other specialists within EOC. Non-emergencies, doctor transport requests and inter-hospital transfers are handled by specific routes.
The EOC is also where FRED lives. I don't like FRED.