RC4Magic Series 3 DMXio User Manual
Page 8
DMX Termination
A DMX terminator is available within the DMXio and can be toggled on/off by pressing one
button. The state of termination (on or off) is remembered and will be restored when power
is cycled. Note, however, that termination is not engaged when the DMXio is not powered
on.
DMXio Transmitter Mode
As a transmitter, the DMXio decodes the DMX universe arriving at the DMX connector,
encodes and encrypts it, and broadcasts it using Direct Sequence Spread Spectrum (DSSS)
digital radio. Unlike wired DMX, the RC4 wireless signal includes error checking and
correction codes, and is not affected by minor interruptions and interference. DMX channels
that are changing are allocated more bandwidth than channels that are not changing, and all
channels are broadcast with appropriate speed, redundancy and accuracy.
Channel Range Limiting
By default, the DMXio transmits the entire DMX universe arriving at the wired DMX data
input. The universe can be any number of channels from one to 512. The maximum number
of channels in a DMX universe is 512, but some controllers produce fewer (some common
numbers of channels are 64, 128, and 256).
To reduce wireless bandwidth consumption, it is sometimes desirable to limit the number of
DMX channels actually being transmitted. For example, if you are using RC4Magic to
wirelessly control two DMX4dim wireless dimmers, with a separate DMX channel assigned
to each dimmer, you only need to transmit data for eight channels. If they are contiguous
channels (say, 400 – 407), then limiting the transmitter to just that range reduces wireless
bandwidth by as much as 99.98%!
If you’re not sure how many channels you are using, or if you are using DMXio units for full-
universe cable replacement, stay with the default settings and transmit the entire universe.
DMXio Receiver Mode
As a receiver, the DMXio decodes the wireless signal from the transmitter, rebuilds the DMX
universe, and regenerates a standard DMX signal with the same number of channels and the
same packet rate as the data going into the transmitter. DMX in and out are compliant with
USITT DMX512/1990.