Customer                                                                                                                                               Sales                                                                                                    
                                                                                                                                                                                                                                                                         
                                                                                                                                                                   SEND                                     report                                                       
                                                                                                                                                                   to customer                                                                                           
                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                         
                                                                                                           in big envelop                                                                                                                                                
                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                         
                               RECEIVE                                                                                 report                                                                                                                                            
                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                         
                                                                                                                                        by mail                                                                                                                          
                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                         
                                                                                                                                                                              RECEIVE                                                                                 ack