   encode: () ->
     _buffers = [
       '',
-      new Buffer([@id, 0, 0, 0]),
+      @fixed_fields(),
       @abstract_syntax.encode()
       Buffer.concat(_ts.encode() for _ts in @transfer_syntax)
     ]

    _buffers[0] = _header
    return Buffer.concat(_buffers)

  to_json: () ->
    _json = super()
    _json.id = @id

ITEM_BY_NAME =
  'application_context': ApplicationContextItem
  'presentation_context': PresentationContextItem
  'presentation_context_ac': PresentationContextItemAc
  'abstract_syntax': AbstractSyntaxItem
  'transfer_syntax': TransferSyntaxItem
  'user_information': UserInformationItem
