Marine Electronics Forum - NMEA connections

Here's one I haven't see posted before.

I recently purchased a second GPS for my boat so I have a backup. The original is a Garmin handheld and the new one is a Furuno GP31 (new left over for around $120). I'm going to make the Furuno the primary. I would like to have both of them feeding NMEA data to my DSC equipped VHF and fishfinder (the Garmin currently does). With two different incoming streams of NMEA data, is that going to greatly confuse the FF and VHF? Am I getting ahead of myself here and should I just connect both and turn off the NMEA out on the backup unit until I need it (hope that never occurs).

I already know how to make the proper connections, so that is not an issue.

Thanks.

Brian
1985 Grady White 204 Center Console
http://userpages.umbc.edu/~bmille4/sirreel/index.html

i have both a furuno gp 37 and an 1850. i have both nmea out interfaces hooked up to the same point with interfaces to an a/p, radar, vhf (dsc) and ff and do exactly as you suggest...i use the 1850 and the gp37 nmea out sentences are currently turned off. i'll turn them on if the 1850 craps out on me at some point.

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Capt. Adam
Karen Ann II
http://www.karenannii.com/images/tht/karenannii_tht.jpg

I'm pretty sure NMEA 0183 only supports one talker at a time. It is likely that the two units will walk on each other and garble the messages since it's a two wire data buss and there's no coordination between units on the timing of messages. I believe Captadamnj is right, you'll have to silence one of the units until you need it.

"A bad day fishing is better than a good day in the office."