This is the ValueSet that contains all the codes in TelecommunicationCapabilities (http://terminology.hl7.org/ValueSet/v3-TelecommunicationCapabilities) and TelecommunicationCapabilities (http://terminology.hl7.org/ValueSet/v3-TelecommunicationCapabilities). E.g. what you have to deal with if you get resources containing codes in either of them