ANSI E1.20 - 2010 Entertainment Technology RDM Remote Device Management Over DMX512 Networks
A device may contain one or more sub-devices, all having a common set of parameters. An example of a device with sub-devices is a dimmer rack containing a number of dimmer module sub-devices.
Sub-devices can only ever exist as part of a root device. Sub-devices may not themselves contain sub-devices.
ANSI E1.20 – 2010, Entertainment Technology – RDM – Remote Device Management over DMX512 Networks
Supported Sub-Devices: http://www.raspberrypi-dmx.org/raspberry-pi-dmx512-rdm/rdm/built-in-supported-sub-devices