Help with AIS data to Garmin 740S

[OldManMirage]

Here's my situation.

I have a Standard Horizon 2200GX with AIS data out. There are positive and negative wires, yellow and white respectively.

The Garmin 740S has "Serial Ports" for input of AIS data showing only a positive in.

So am I correct in assuming the negative from the 2200GX would just go to ground ?

Do I need to fuse these connections in any way ?

Lastly, has anyone done this and what does it look like on the Garmin screen ?

Thanks in advance to all who contribute.

[VBsail]

Yes, use the Garmin negative for the nmea negative and under Garmin settings, communication, set the nmea port to high speed.

[smac999]

you never ground a nmea output -, only the input - if needed. just leave it open and only connect the A / + and it'll likly work.

[Tsuru]

I installed a DAISy AIS receiver on a Garmin 740 or 741 years ago. I think smarv999 is correct but can’t really recall. I remember is was easier than I thought it would be. In operation it had full view on the Garmin screen. You could set distance and other alarms on the Garmin control menu. Easy function and cost effective upgrade

[stevead]

I think I should change my signature to "Why do manufacturers bother publishing manuals when no one reads them"

From page 5 of the Garmin GPS Map 700 series installation manual.

[OldManMirage]

Ok, my manual doesn't have that specific diagram nor does it answer the question I had about the negative AIS data output from the GX2200.

But, I will try it with just the positive connected to the Garmin and see how that goes.

Mostly don't want to short something out !

[smac999]

Originally Posted by stevead

I think I should change my signature to "Why do manufacturers bother publishing manuals when no one reads them"

From page 5 of the Garmin GPS Map 700 series installation manual.

This works if the unit is 232 with a common ground nmea wire. (And if it’s common ground it’s already grounded inside which makes the outside ground unneeded) If the device is 422 both wires have a signal and you just grounded one side of it’s output potentially damaging the device.

It’s best not to ground the nmea output if it there is nowhere to put it, and if works without it.

[stevead]

Which is described in the Standard Horizon manual....

[OldManMirage]

Yep, found that on the internet too.

Unfortunately, for whatever reason I couldn't get them to talk to each other.

I'm fairly certain I have everything correct in the configuration of both units. I had the output of the GX2200 set to 38,400 baud. Had the Garmin set to high speed for the input. It SEEMS pretty straight-forward but...

I tried a couple of different connections with and without grounding the data output from the GX2200.

But nothing ever showed up on the 740S screen.

Guess I might try calling tech support unless anyone has any better ideas ?

[OldManMirage]

So, just to follow up and finish this thread I did give Garmin a call. It was fairly easy and although the wait time was long you can set up a call back rather that sit on hold.

Anyway, spoke with Gabe and we walked through several things with no luck. He did recommend taking the AIS negative from the GX2200 and running it to a common ground.

We confirmed the GX2200 was putting out data by checking for voltage and it was.

Towards the end of the call when it seemed like it wasn't going to happen we tried switching to Serial Port 2 on the Garmin and lo and behold targets started popping up on the screen. Even though the setting were same for Port 1! But hey, don't look a gift horse in the mouth right ?

Interestingly, the targets would come and go. We attributed this to the fact that I was using multiple test lead wires with alligator clips and my connections were "iffy" at best. Hard wiring it in should improve connections and reliability.

[CaptTom]

Thank you for the follow-up. I was curious to see how this ended.