This code system http://terminology.hl7.org/CodeSystem/verificationresult-communication-method defines the following codes:

CodeDisplayDefinition
manual ManualThe information is submitted/retrieved manually (e.g. by phone, fax, paper-based)
portal PortalThe information is submitted/retrieved via a portal
pull PullThe information is retrieved (i.e. pulled) from a source (e.g. over an API)
push PushThe information is sent (i.e. pushed) from a source (e.g. over an API, asynchronously, secure messaging)
 <status value="active"/> <experimental value="false"/> <date value="2018-10-31"/> <publisher value="HL7 International"/> <contact> <telecom> <system value="other"/> <value value="http://hl7.org/fhir"/> </telecom> </contact> <contact> <telecom> <system value="other"/> <value value="http://hl7.org/fhir"/> </telecom> </contact> <description value="Attested information may be validated by process that are manual or automated. For automated processes it may accomplished by the system of record reaching out through another system's API or information may be sent to the system of record. This value set defines a set of codes to describing the process, the how, a resource or data element is validated."/> <caseSensitive value="true"/> <valueSet value="http://terminology.hl7.org/ValueSet/verificationresult-communication-method"/> <content value="complete"/> <concept> <code value="manual"/> <display value="Manual"/> <definition value="The information is submitted/retrieved manually (e.g. by phone, fax, paper-based)"/> </concept> <concept> <code value="portal"/> <display value="Portal"/> <definition value="The information is submitted/retrieved via a portal"/> </concept> <concept> <code value="pull"/> <display value="Pull"/> <definition value="The information is retrieved (i.e. pulled) from a source (e.g. over an API)"/> </concept> <concept> <code value="push"/> <display value="Push"/> <definition value="The information is sent (i.e. pushed) from a source (e.g. over an API, asynchronously, secure messaging)"/> </concept> </CodeSystem>