This is the ValueSet that contains all the codes in Simple Alert Operational States (http://hl7.org/fhir/uv/phd/ValueSet/SimpleAlertOperationalStates) and Simple Alert Operational States (http://hl7.org/fhir/uv/phd/ValueSet/SimpleAlertOperationalStates). E.g. what you have to deal with if you get resources containing codes in either of them