description: To be used when the actual gateway used at the time of the observation, and the referenced device is also specified. The gateway device may be acting as a communication/data collector, translator or controller; This extension is useful when there is more than one gateway device, for example, where there are apps on a phone and each are a device, and more than one app is used to pass on the data to a FHIR Server. In that case you need to be able to say from the observation which specific app was used to act as gateway. Note that the Provenance/AuditEvent resources can represent the same information. Use Device Gateway (device-gateway) extension which allows codeableReference (Device) in R6 and requires cross version extension for codeable reference.
package_name: hl7.fhir.uv.extensions.r4b
derivation: constraint
name: ObsGatewayDevice
type: Extension
elements:
  extension: {index: 0}
  url:
    pattern: {type: Uri, value: 'http://hl7.org/fhir/StructureDefinition/observation-gatewayDevice'}
    index: 1
  value:
    choices: [valueReference]
    index: 3
  valueReference:
    type: Reference
    choiceOf: value
    refers: ['http://hl7.org/fhir/StructureDefinition/Device']
    index: 4
package_version: 5.3.0-ballot-tc
extensions: {}
class: extension
kind: complex-type
url: http://hl7.org/fhir/StructureDefinition/observation-gatewayDevice
base: http://hl7.org/fhir/StructureDefinition/Extension
version: 5.3.0-ballot-tc
required: [valueReference, value]