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The
different mode DMX512 signal are transmitted in 120 ohm
screened twist cable. When the cable is joined to the XLR
port, the colors of two core lines have to be identified.
If one port is connected in reverse, the equipment
following can’t work rightly. 1connection of the XLR
port is connected to the screen net of the cable. 2
connection is connected to the negative end of the cable.
3 connection is connected to the positive end of the
cable.
It is
proposed to use the high quality . If the whole length of
the cable is not long, the cable may be replaced by the
high quality phone cable with tight screen net and large
section core line.
This
bus connection is called "chrysanthemum
chain" also.
In
a data bus:
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Only
one equipment (console) can send data. Other equipment
all are the terminal units and they ceaselessly
received the signals sent by the console.
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The
whole length of the cable can’t exceed 250m.
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In
the end of the data cable, a terminal impedance
matching resister must be connected to prevent the
reflection of the signals. The reflection signals can
make the terminal device receive the wrong data. When
the dada cable is quite long, the appearance of the
fault code will increase.
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