The VL-SDN is used for the distribution of redundant NMEA. With its 2 galvanically isolated NMEA inputs, the module automatically choose between the two inputs, and then forward it to 12xRS422 and 2xRS232 outputs. If the main input does not receives any signals, the module is then automatically switches to the second input. An option of manual switching between 2 inputs is also possible. Through 2 voltage inputs, the power supply 9-32VDC is designed as a fail-safe (MSB-ESB).