IR DEFINITIONS ::=  
BEGIN   -- ANSI Z39.50 version 2 - July 1, 1992      
PDU ::= CHOICE{
  initRequest                 [20] IMPLICIT InitializeRequest,
  initResponse                [21] IMPLICIT InitializeResponse,
  searchRequest               [22] IMPLICIT SearchRequest,
  searchResponse              [23] IMPLICIT SearchResponse,
  presentRequest              [24] IMPLICIT PresentRequest,
  presentResponse             [25] IMPLICIT PresentResponse,
  deleteResultSetRequest      [26] IMPLICIT DeleteResultSetRequest,
  deleteResultSetResponse          [27] IMPLICIT DeleteResultSetResponse,
  accessControlRequest        [28] IMPLICIT AccessControlRequest,
  accessControlResponse       [29] IMPLICIT AccessControlResponse,
  resourceControlRequest      [30] IMPLICIT ResourceControlRequest,
  resourceControlResponse          [31] IMPLICIT ResourceControlResponse,
  triggerResourceControlRequest    [32] IMPLICIT TriggerResourceControlRequest,
  resourceReportRequest       [33] IMPLICIT ResourceReportRequest,
  resourceReportResponse      [34] IMPLICIT ResourceReportResponse}
END