code: def encode(self, pdu):
          
          if _debug: BVLCI._debug("encode %s", str(pdu))
  
          # copy the basics
          PCI.update(pdu, self)
  
          pdu.put( self.bvlciType )               # 0x81
          pdu.put( self.bvlciFunction )
  
          if (self.bvlciLength != len(self.pduData) + 4):
              raise EncodingError("invalid BVLCI length")
  
          pdu.put_short( self.bvlciLength )
docs: encode the contents of the BVLCI into the PDU.