AutomationDirect devices (including device models DL-05, DL-06, DL-205, and DL-405) have CPUs that use Firmware to know how to work with the I/O and communications modules. As such, users must update the CPU to the latest Firmware version any time that they get a new controller or upgrade modules in the rack. For a complete list of Firmware revisions, refer to AutomationDirect Firmware.