Optosplitter
An Optosplitter, or Optically Isolated Splitter, is a device for splitting a DMX signal across multiple lines or cable runs.
Because of the limits of carrying DMX data, it is not possible to simply splice cables together to extend and split DMX lines (this is called "Passive Splitting"). Instead, an active splitter device must be used, which actually repeats the signal onto each new line. With an optosplitter, each of these lines is completely isolated so that any fault which develops down one line is not passed on to any others.
Each new line will require a terminator - though unused Optosplitter outputs need not be terminated.