I have one of those so I could use my existing (and installed) ST50-era transducers with a much newer MFD layout. The itc-5 only converts the analog xducer inputs to RM's SeaTalk/ng bus, not normal NMEA2k as far as I can tell from the installation
manual. Now, there's another little RM gizmo that converts SeaTalk/ng to NMEA2k but I I have no personal experience with it. It very well might work
though, probably run about the same as the price
of an itc-5 to get all the extra cables
and stuff together.