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I am interested in upgrading my old furuno LS4100 to a FCV620 or FCV585 unit. It is my understanding that these units including my older unit have the capability to mark waypoints on the sonar screen when attached to a gps signal via a NMEA connection. I think this is such an invaluable feature since I spend most of my time fishing/diving structure. I cant tell you how many times I have run over a mark where I had tried to turn around with out finding it. This feature seems to eliminate that frustration.
Currently I have a garmin 4208. When I purchased this unit I had the mind set that I would later add the GSD22 sounder to the unit. Unfortunately, Garmin did not do such an outstanding job with respect to there sonar capabilities especially with the feature mentioned above and from my research the Furuno is really second to none when it comes to fish finding, it clearly shows.
I have been tortured for the past couple of months about getting rid of my 4208. I have called Garmin and Furuno asking them what type of data exchange is possible between units and they haven’t been able to answer any of my questions. The main question being can the furuno mark waypoints on the sonar screen using the gps signal for the 4208? Meaning if I run over a mark can I scroll over to the point of interest on the sonar and capture that waypoint? In addition if this is the case can the two units share waypoint information? Meaning if I capture a WP on the Furuno can I migrate that WP to the garmin via the network since I would like to keep the garmin as my only source of navigation?
There is a note ther that the unit outputs a NEMA 0183 statement called TLL to the GPS when a waypoint is marked on the sounder.
I guess it depends on if the Garmin accepts a TLL data statement on its NMEA input or not.
There must be two ways to configure how the TLL is sent. One must be propietary to FURNUO, called FURUNO TLL format and the other just plain TLL. That format would be set depending on what the reciever (GPS) expected in that Statement. Obviously a FURUNO would likely expect the FURUNO format.
My guess is that this statement is TRANSMITTED LAT/LONG for a waypoint and may not yet be part of the NMEA standard????????
Garmin says they recognize all standard NMEA statements. (Garmin als does some private stuff with NMEA.)
Kinda like the old days, I guess??? Trying to run Windows on top of DOS!
__________________ Dog Tired
I'm for a government that is by the people and for the people!
TLL stands for Target Lat/Lon. Still think it depends on if the Garmin gets the sentence and then what it does with it.
TTL is Lat/LON
Furuno TTL is LAT/LON with temp and depth as well.
The Navnet3d does not except the input from the 585 so I would want to have some one confirm before buying. The 585 is a great fish finder and I was was under the impression that I could get it to transfer data like it worked on the Navnet2 system.
If you have a NMEA LAT/LON feed into the 585 it will save 20 waypoint as a stand alone system. So you can then navigate back to a point using the 585.
The 4208 can transmit position data L/L to the 585. Likewise the 585 can transmit a Marked position back to the 4208; HOWEVER, you can count on some latency and inaccuracy due to the timing of the messages. In other words, when you Mark on the Furuno, you will be using the last (but not necessarily current) position data transmitted by the Garmin and processed by Furuno.
It likely isn't much, but when marking spots it would be more accurate to mark using the 4208. It also makes more sense to Mark with the Garmin as the 585 has the capacity to store only 20 Marks - then you have to go in and erase some for more room. If the que is filled, you'll get an error message that may result in your missing a Mark.
I think what Furuno is doing is logging a lat/long in a buffer for each line of the FF display. When you use the cursor to back in time historically on the FF screen and hit mark it pulls your old position from where you were when you crossed that point.
That is the position information transmitted back to the GPS. No latency!
__________________ Dog Tired
I'm for a government that is by the people and for the people!
You will always mark late; the GPS is a few milliseconds behind, it reports position to the FF a few milliseconds later, and your personal response time is even slower. That translates to a yard or two if the boat is moving at trolling speed, to quite some distance if you are cruising. Slow down in the general vicinity, and mark with the GPS. Then do a 270 to cross it on a perpendicular heading. You have the best chance of going back to that spot if you shoot for right between them. If you want to be anal about it do three 270's.
Don't expect to get one set of off sets for all your loran spots. The variation between GPS and Loran positions changes from area to area.
__________________ If it ain't broke, I haven't played with it.
I think what Furuno is doing is logging a lat/long in a buffer for each line of the FF display. When you use the cursor to back in time historically on the FF screen and hit mark it pulls your old position from where you were when you crossed that point.
That is the position information transmitted back to the GPS. No latency!
The 4208 can transmit position data L/L to the 585. Likewise the 585 can transmit a Marked position back to the 4208; HOWEVER, you can count on some latency and inaccuracy due to the timing of the messages. In other words, when you Mark on the Furuno, you will be using the last (but not necessarily current) position data transmitted by the Garmin and processed by Furuno.
It likely isn't much, but when marking spots it would be more accurate to mark using the 4208. It also makes more sense to Mark with the Garmin as the 585 has the capacity to store only 20 Marks - then you have to go in and erase some for more room. If the que is filled, you'll get an error message that may result in your missing a Mark.
Do you have personal experience with respect to the this bi-directional data exchange?
On a previously ownd Grady My setup included a Furuno 582, Garmin 182C Furuno 511 Autopilot and Furuno 1732 Radar/ Chartplotter.
The interface wiring is generally straightforward but many folks get messed up when it comes to setting up the communications; that is setting baud rates, versions and turning on/off the various sentences.
Furuno to Garmin functionality data exchange? 
