This code system http://hl7.org/fhir/v2/0912 defines the following codes:

CodeDisplayComments
ADAdmitting ProviderPV1-17 Admitting doctor
AIAssistant/Alternate Interpreter
APAdministering ProviderRXA-10 Administering Provider
ARIAssistant Result Interpreter
ATAttending ProviderPV1-7 Attending doctor
AUTAUT Author/Event InitiatorORC-19 Action By
CPConsulting Provider
DPDispensing ProviderRXD-10 Dispensing Provider
EPEntering Provider (probably not the same as transcriptionist)ORC-10 Entered By
EQUIPEquipment
FHCPFamily Health Care Professional
MDIRMedical DirectorOBX-25 Performing Organization Medical Director
OPOrdering ProviderORC-12 Ordering Provider, OBR-16 Ordering Provider, RXO-14 Ordering Provider's DEA Number, RXE-13 Ordering Provider's DEA Number, ORC-24 Ordering Provider Address
OSOutside Site(s) Where Observation May Be PerformedReplacing OM1-27 Outside Site(s) Where Observation May Be Performed
PBPacked by
PHPharmacist (not sure how to dissect Pharmacist/Treatment Supplier's Verifier ID)RXE-14 Pharmacist/Treatment Supplier's Verifier ID
PIPrimary Interpreter
POPerforming Organization
POMDPerforming Organization Medical Director
PPPrimary Care Provider
PRIPrincipal Result Interpreter
RCTResults Copies To
ROResponsible ObserverOBX-16 Responsible Observer
RPReferring ProviderPV1-8 Referring doctor
RTReferred to Provider
SBSend by
SCSpecimen CollectorOBR-10 Collector Identifier
TNTechnician
TRTranscriptionist
VPVerifying ProviderORC-11 Verified By
VPSVerifying Pharmaceutical Supplier (not sure how to dissect Pharmacist/Treatment Supplier's Verifier ID)RXE-14 Pharmacist/Treatment Supplier's Verifier ID
VTSVerifying Treatment Supplier (not sure how to dissect Pharmacist/Treatment Supplier's Verifier ID)RXE-14 Pharmacist/Treatment Supplier's Verifier ID
WAYWaypoint
WAYRWaypoint Recipient