An affordable (~100 USD) four output DMX512 opto-splitter by Australian manufacturer Enttec.
http://www.enttec.com/index.php?main_menu=Products&pn=70572
Available in two versions: one (as shown above) has two XLR3F and two XLR5F outputs; the other has four XLR5F outputs.
http://www.enttec.com/index.php?main_menu=Products&pn=70572
Available in two versions: one (as shown above) has two XLR3F and two XLR5F outputs; the other has four XLR5F outputs.