RDM stands for Remote Device Management.It is a protocol enhancement to USITT DMX512 that allows bi-directional communication between lighting consoles and RDM compliant devices over a standard DMX line.So it allows configuration, status monitoring and management.To use RDM, you need an RDM-enabled DMX controller and fixtures that are RDM compatible and compliant. If you use DMX splitters, these will also need to be RDM-enabled and compliant as well.