This is the ValueSet that contains all the codes in C4DIC Contact Type (http://hl7.org/fhir/us/insurance-card/ValueSet/C4DICContactTypeVS) and C4DIC Contact Type (http://hl7.org/fhir/us/insurance-card/ValueSet/C4DICContactTypeVS). E.g. what you have to deal with if you get resources containing codes in either of them