RPN: 479V Viper Responder Replacement Remote Remote Compatibility: System Model Number System Part Number Date Code If you see "All" in the Date Code column then the remote will work with any versions of the corresponding system. Most newer systems have the "All" designation. If you see a value (such as 8D-9A), then the remote will only work with a subset of the system produced during a certain time period. This is only the case for some older systems. If you have one of these older systems, here is how to find the date code: 591 XV 542V All 690 XV 434V All 790 XV 554V All 791 XV 564V All