mDMX is the latest in the line of data
transmission products from Avolites.
mDMX sends multiple 512 channel DMX universes over mains cable at normal
DMX data transfer speed.
Using mDMX there is no need for a separate DMX cable saving time and cost,
fixtures can either have mDMX receivers built in, or use an mDMX receiver
which distributes DMX in the usual way.
Unlike wireless systems which will always be susceptible to interference,
mDMX uses cable giving it “cable reliability”.
Cable lengths of at least 250 meters carrying 4 DMX universes can be used.
Additional universes can easily be accommodated by using a second mains
cable.
mDMX is compatible with Avolites’ eDMX thus completing a toolkit of data
transfer products and by providing a fully integrated solution the most
appropriate technology can be selected, mixed and matched.
About mDMX.
mDMX is a unique and highly reliable and
innovative method for sending DMX over mains cabling using Ethernet. mDMX
uses multiplexing technologies to modulate multiple universes of DMX down
a standard mains cable. The attraction of running just one cable is
obvious and mDMX has been designed for situations where data cable
management is a problem e.g. moving trusses and scenery, FOH data runs,
etc.
mDMX currently has a proven capacity of 4 DMX universes running
concurrently over a distance of up to 250 meteres. mDMX is fully
compatible with the versatile and popular Avolites eDMX wireless system.
Importantly unlike wireless systems mDMX does not share bandwidth with
other devices making it “cable reliable” and therefore can be considered
virtually interference free and certainly as interference free as a
standard DMX cable.
How it Works.
mDMX coverts the DMX 512 data into
Ethernet packets using the WENDI protocol. These packets are then
processed using an enhanced form of orthogonal frequency-division
multiplexing (OFDM) with forward error-correction, similar to the
technology found in DSL modems. In the case of OFDM, the available range
of frequencies on the mains cable subsystem (4.3 MHz to 20.9 MHz) is split
into 84 separate carriers. OFDM sends packets of data simultaneously along
several of the carrier frequencies, allowing for increased speed and
reliability.
If noise or a surge in power usage disrupts one of the frequencies, mDMX
will sense it and switch that data to another carrier. This rate-adaptive
design allows mDMX to maintain an Ethernet-class connection throughout the
mains cable without losing any data.
Currently mDMX is rated at 14 Mbps, which is faster than most wireless
solutions [wireless DMX not wireless Ethernet], and makes it compatible
with eDMX (Avolites’ wireless technology).
mDMX is based on an international standard which governs data throughput
and RF interference.
mDMX limits the amount of RF interference through the
low power transmission system employed.
mDMX does NOT use, and should not be confused with BPL (Broadband over
Power Line) technologies, which is not a ratified IEEE standard at this
time. The underlying technology used by mDMX is licensed for use by FCCI,
and ETSI. mDMX is patent pending.
mDMX will be available in November 2006.
Contrasting Wireless and Mains DMX systems.
There are obvious crossovers between
Wireless and Mains DMX, where either could be used and there is little to
choose between them, then mDMX should be chosen since it is inherently
more robust.
There will be some circumstances where Wireless can only be used, for
instance when crossing a river, or road, elsewhere mDMX is far more
suitable: within a building where there are walls which make wireless
reception difficult; incorporating into an existing building when it is
very costly to add new cables; and the obvious use for trusses etc.
By creating an integrated solution the most appropriate technology can be
selected and these mixed and matched to create the most ideal solution.
