RDM (lighting)

Remote Device Management or RDM is a protocol enhancement to USITT DMX512 that will allow bi-directional communication between a lighting or system controller and attached RDM compliant devices over a standard DMX line. This protocol will allow configuration, status monitoring, and management of these devices in such a way that does not disturb the normal operation of standard DMX devices that do not recognize the RDM protocol.

The standard was developed by the ESTA Technical Standards [http://www.esta.org] and is officially known as "ANSI/ESTA E1.20, Entertainment Technology - Remote Device Management over USITT DMX512"

The standard can be purchased from the ESTA Foundation [http://www.estafoundation.org] or ANSI [http://webstore.ansi.org/ansidocstore/product.asp?sku=ANSI+E1%2E20%2D2006]

Disclaimer

__NOEDITSECTION__Information from this page should not be taken as authoritative source but as gateway to information as it becomes available. By no means should this article be used for the purposes of creating an RDM compliant device over any documents set fourth from ESTA Technical Standards Working Group.

Uses for RDM

Since the RDM protocol travels on top of the DMX512 protocol most of its uses will be in the field of stage lighting.Many companies like Wybron [http://www.wybron.com] Artistic Licence [http://www.artisticlicence.com] and Pathway Connectivity [http://www.pathwayconnect.com] are leading the charge for this new protocol although it is thought that many other companies are already using undisclosed RDM like protocols.

This protocol will change the way that Lighting Technicians setup and maintain their lighting rigs, It can provide:
* Identification and classification of connected devices (Fixtures, Dimmers, Splitters, etc...)
* Addressing of devices controllable by DMX512
* Status reporting of fixtures or other connected devices
* Configuration of fixtures and other DMX devices

Learn More

The RDM Protocol forums at http://www.rdmprotocol.org have been established as a community to assist manufacturers and developers implementing RDM in their products or for users seeking more information or questions about RDM. The site is not operated or affiliated by ESTA, but it is the best source of information as many of the developers for the RDM Protocol are active there.

How does it work?

RDM uses interleaved alternate-start-code packets to transmit data to supported devices thus not adding any data that standard DMX devices would consider valid level information.All RDM devices on the link have a unique identifier (UID) that consists of a manufacturer ID and serial number; the controlling device can then use a “discovery” procedure to acquire and UIDs of all connected devices and would then be able to communicate to a specific device or in groups by manufacturer.When a device needs to respond to a controlling device the DMX bus is turned around which means the controller is now listening and the device sends data onto the DMX bus. The standard specifies a specific time window in which this must happenDMX Splitters will now need to be aware of RDM and will need some sort of processing device that listens to the DMX/RDM traffic and act accordingly. This makes all existing splitters obsolete.

External links

* [http://www.rdmprotocol.org RDM Protocol Developer and User Forums]
* [http://www.usitt.org/standards/DMX512_FAQ.html#FAQ_17 What is RDM?]
* [http://www.wybron.com/Entertainment/Watchdog_3/RDM.pdf Wybron RDM Documentation (PDF)]
* [http://www.enttec.com/rdm ENTTEC RDM tools and RDM equipment]
* [http://www.ukslc.org/Technical_Articles/Lighting/Guide_to_RDM_%28Remote_Device_Management%29.html Guide To RDM]