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:
· Only one equipment (console) can send data. Other equipment all are the terminal units and they ceaselessly received the signals sent by the console.
· The whole length of the cable can't exceed 250m.
· 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.