Model: NM-541 MUX 
5-channel NMEA multiplexer with Serial, USB, RS-422 & Ethernet  

NM-541MUX is a four or five input channel multiplexer with five output channels NMEA-0183 data multiplier. It enables combining and multiplying of all NM-0183 sources to the navigational instruments through five talker ports and PC connection through RS-232, USB and an optional Ethernet interface.

Model: NM-251A-MUX
NMEA Buffer Splitter with dual input multiplexer

NM-251A-MUX is a two input channel multiplexer with five output channels NMEA-0183 data multiplier. It enables combining and multiplying of NM-0183 sources to all navigational instruments through five talker ports and PC connection through RS-232.
Certificates

NM-251A NMEA Buffer & Dual multiplexer