Optical star coupler for central operation from siemens protect. equipments v3 w. protection operator routine digsi v3, basic design in subrack 19" single-height with central controller module for connecting on pc or modem over lwl 820nm fsma-plug or sub-d 9pol. bush auxiliary supply 48-250v dc and 110-220v ac without change-over for connection over lwl 820nm fsma-plug for 6 protection equipments