Luminite 4 zone xpander module. Relay expansion module for RX16 This module plugs on to the RX16 mother board to give an extra 4 outputs. The RX16 comes with one module as standard which acts on codes 1 to 4. If a PC4 is plugged on to the second position it will act on codes 5 to 8. The third position is 9 to 12 & the fourth is 13 to 16.