From which incident facility does the Incident Commander oversee incident operations?

Command Post. It is a sort of job title and not necessarily a fixed structure- could be say, a firehouse or emergency amubulance station, or a Police Radio station with adequate command and signal facilities. Many police departments have special ( Signal emergency) or communications emergency trucks with many multi-band radio apparatus installed. This often is used in the case of such minor but disruptive to communications events as, say- Power failures.