Need help with NMEA interfacing

[Quickstep192]

I have a Raymarine Chartplotter and a Furuno FishFinder. I want to make the NMEA connection between the two so my FishFinder has bearing and position data. Is this as simple as connecting the input leads from the FishFinder to the output leads of Chartplotter and vice versa?

Also, the Raymarine uses the terminology "+" and "-" to reference the leads, Furuno uses "H" and "C". Do I connect the "+" lead from the Raymarine to the "H" lead from the Furuno and the "-" lead to "C"? (I assume H and C refer to Hot and Common?)

[ereuter]

That should work fine, and yes, I think you've assumed correctly about the polarities.

I don't have any specific knowledge of that equipment, but NMEA inputs and outputs are generally compatible. If the chartplotter is outputting more information (such as manufacturer-proprietary data), the receiving device should just ignore it.

Eric

[sailingdog]

Be aware that some NMEA equipment suppliers, particularly Garmin, use the 12 VDC system ground as the signal ground. Haven't done enough work with Furuno to know if they do the same thing. IIRC, it is because some vendors implement NMEA 0183 as a RS-232 port and others implement it as an RS-422 port.