1 GPS to 2 Listeners, ie AIS + openCPN.

[nixontankgirl]

Sorry, I am sure this has been covered in many other threads, but after looking through, I couldn't find either a thread that was applicable to my situation or alternatively one that I can understand.....

So, I have a Garmin Etrex plugged into my laptop, via a serial port, and running with OpenCPN.

I have a 2nd Garmin Etrex that is hard wired to my Icom DSC VHF. I literally chopped the end off the Garmin data cable and twisted the wires together.

I have now got an AIS receiver.

So, my question is; Can I simply 'twist' the AIS GPS input wires around the join that go from from the second GPS to the VHF?

I hope the answer is 'yes'....

Or does it matter that the GPS that is plugged into the laptop isn't the same one as the AIS is using?

[Albro359]

You have a GPS connected to the laptop
You have another GPS connected to the radio

If I were you I would connect the AIS GPS input to the GPS that's connected to the laptop....that would avoid any conflicts due to timing issues

But you could try it the other way and see what happens !!

[nixontankgirl]

Yep, but I am hesitant to cut into the wire from the GPS to the laptop, and I have tried plugging the GPS with the chopped wire into the laptop and it didnt work....but that may of had something to do with my homemade USB cable and probably a lack of drivers....

So, if I am to join the GPS that is currently plugged into the laptop to the AIS also, how can I do it?

That is why I was hoping to be able to join it to the VHF. I am not on board until the end of the month and I am hoping to take anything I may need with me.

I guess you kept out of the flooding up there?

[Albro359]

Not sure what your connection is....is it USB or RS232 serial.....if its RS232 serial and you have a serial to USB converter plugged into your laptop, and the AIS needs an RS232 input then just parallel the wires..usually +,-, GND so the signal from the GPS will go to the AIS and the laptop at the same time.

If its all USB, then someone else maybe able to help.

Good luck.....yes no flooding at Vuda Point

[Viking Sailor]

Originally Posted by nixontankgirl

Yep, but I am hesitant to cut into the wire from the GPS to the laptop, and I have tried plugging the GPS with the chopped wire into the laptop and it didnt work....but that may of had something to do with my homemade USB cable and probably a lack of drivers....

So, if I am to join the GPS that is currently plugged into the laptop to the AIS also, how can I do it?

That is why I was hoping to be able to join it to the VHF. I am not on board until the end of the month and I am hoping to take anything I may need with me.

I guess you kept out of the flooding up there?

Most AIS receivers have an input for a VHF antenna, another input for the GPS data, and an output for the AIS data to a computer. It is often the case that the GPS data is included in with the AIS data that goes to the computer. OpenCPN is designed to accept this combined data stream as its sole input for both the GPS data and the AIS data.

It would help if you can provide the following info:

Which AIS receiver are you using?

Is the GPS input to the AIS receiver RS-232 or USB?

Is the AIS data output from the AIS receiver RS-232 or USB?

Is your GPS connected to the computer via a RS-232 serial, or USB connection?

Is the GPS connected to the VHF radio via a RS-232 serial, or USB connection?

[nixontankgirl]

Originally Posted by Albro359

Not sure what your connection is....is it USB or RS232 serial.....if its RS232 serial and you have a serial to USB converter plugged into your laptop, and the AIS needs an RS232 input then just parallel the wires..usually +,-, GND so the signal from the GPS will go to the AIS and the laptop at the same time.

If its all USB, then someone else maybe able to help.

Good luck.....yes no flooding at Vuda Point

The GPS to the laptop; I have a serial/USB converter and also just a serial plug and it works with both.
The AIS; Has just 2 bare wires. That's why I had been hoping to twist them onto the other GPS.
Am I making sense?

So, I am little confused

[HappySeagull]

...so, you have two serial ports available.Do you have a spare serial port type plug handy that you can play with? I'd ignore the second gps aspect or freaking with the one that's working and just fiddle with the ais through its own port.
Given Albro359's expertise (I haven't an AIS) it would seem that this might work-
hooked up as an old time handheld gps would be(data out and signal ground) ..and fiddle with that first. If you don't have a spare comport end available, it IS possible to haywire direct to the comport pins with automotive-type push-on connectors that are squeezed to fit the pins...+ uglytape or shrinktube to cover from accidental contacts etc...

Added I wouldn't have the AIS running to two places at once YET...until I knew it worked in each alone....and I knew that ground was at the same potential for each device! and I knew if whether or not I could insulate the two using diodes ...ie-the ais signal's voltage works minus the half volt of a diode...other things have for worked with this funky insurance for me. ..

[nixontankgirl]

Originally Posted by Viking Sailor

Most AIS receivers have an input for a VHF antenna, another input for the GPS data, and an output for the AIS data to a computer. It is often the case that the GPS data is included in with the AIS data that goes to the computer. OpenCPN is designed to accept this combined data stream as its sole input for both the GPS data and the AIS data.

It would help if you can provide the following info:

Which AIS receiver are you using?

Is the GPS input to the AIS receiver RS-232 or USB?

Is the AIS data output from the AIS receiver RS-232 or USB?

Is your GPS connected to the computer via a RS-232 serial, or USB connection?

Is the GPS connected to the VHF radio via a RS-232 serial, or USB connection?

Which AIS receiver are you using? AMEC CYPHO-101

Is the GPS input to the AIS receiver RS-232 or USB? It is just a cable that ends in bare wires. The red and the blue are labelled AIS - and AIS +. There is also an RS-232 on the AIS. (I think this is for output)

Is the AIS data output from the AIS receiver RS-232 or USB? Currently USB, but see above.

Is your GPS connected to the computer via a RS-232 serial, or USB connection? USB

Is the GPS connected to the VHF radio via a RS-232 serial, or USB connection? No. Just an antenna connector.

I have seen in the OpenCPN settings/GPS in the drop down box there is the option of sharing the port with an AIS. So I presume after reading what you have said that I now plug my GPS directly into the Serial on the AIS and plug the AIS via USB into the laptop?

[nixontankgirl]

Aha! I think it is all falling into place......said the lemming.

The AIS was bought second hand and didn't come with an instruction book, I had thought the serial on the AIS was an output but I gather it is an input from what everyone has written....

[Viking Sailor]

Originally Posted by nixontankgirl

Which AIS receiver are you using? AMEC CYPHO-101

Is the GPS input to the AIS receiver RS-232 or USB? It is just a cable that ends in bare wires. The red and the blue are labelled AIS - and AIS +. There is also an RS-232 on the AIS. (I think this is for output)

Is the AIS data output from the AIS receiver RS-232 or USB? Currently USB, but see above.

Is your GPS connected to the computer via a RS-232 serial, or USB connection? USB

Is the GPS connected to the VHF radio via a RS-232 serial, or USB connection? No. Just an antenna connector.

I have seen in the OpenCPN settings/GPS in the drop down box there is the option of sharing the port with an AIS. So I presume after reading what you have said that I now plug my GPS directly into the Serial on the AIS and plug the AIS via USB into the laptop?

Here is a link to the manual http://milltechmarine.3dcartstores.c...l_20090112.pdf for your AIS receiver. Check page 20 figure 2-16.

There are three models of this receiver. From your posts I'm guessing that your receiver is the one that does not have the built in GPS receiver. If so, then figure 2-16 should help with getting the connections squared away.

[CarCode]

I use a VHF with buildin AIS. It is the RO4800 from Furuno.
The GPS is connected to the VHF. The RO4800 is configured to transmit GPS together with AIS to its output which is connected to the OpenCPN laptop.
This is the cheapest and easiest solution to receive GPS and AIS for OpenCPN. Works great.

Gerhard

[nixontankgirl]

Originally Posted by Viking Sailor

Most AIS receivers have an input for a VHF antenna, another input for the GPS data, and an output for the AIS data to a computer. It is often the case that the GPS data is included in with the AIS data that goes to the computer. OpenCPN is designed to accept this combined data stream as its sole input for both the GPS data and the AIS data.

It would help if you can provide the following info:

Which AIS receiver are you using?

Is the GPS input to the AIS receiver RS-232 or USB?

Is the AIS data output from the AIS receiver RS-232 or USB?

Is your GPS connected to the computer via a RS-232 serial, or USB connection?

Is the GPS connected to the VHF radio via a RS-232 serial, or USB connection?

I have just installed an AIS, wired the GPS to it and plugged it into the USB. I am finding the wiring diagram a little confusing, I had thought it was going to output a GPS signal via the USB but it doesn't.

I am getting data to my laptop from the AIS. I have changed the port settings.

So, what I want to know is;

Does the AIS need the GPS signal? Are the CPA calculations done in the AIS or OpenCPN?
And in the wiring diagram there are 2 wires TXP and TXN that 'transmit AIS and GPS Data'. I presume if I was somehow to connect those to my laptop then the GPS data would be available via OpenCPN. But how do I connect 2 wires to my laptop? I guess I cant just twist them onto a chopped up USB cable as there are no drivers etc.......

[Viking Sailor]

Based on my understanding of your hardware, this is how you should connect them together.

eTRAX...................AMEC CYPHO-101.........RS-232 (Laptop)

3 DOUT (wht)........3 RXP (wht)

4 GND (blk)...........5 FG (blk).....................5 SG

............................1 TXP (blu)....................2 RD

Hope this helps, and good luck,

[barnakiel]

Originally Posted by nixontankgirl

- Does the AIS need the GPS signal?

- Are the CPA calculations done in the AIS or OpenCPN?

- I guess I cant just twist them onto a chopped up USB cable as there are no drivers etc.......

- some AIS units can take GPS signal and multiplex (join) it with the AIS data then forward the whole packet to the laptop, (but if you go this way, once you switch off the AIS, the laptop will lose the gps data too), see in the manual,

- your unit might accept both GPS data in and (optionally) GPS antena signal in (then it would do the processing within), (read the manual again as there seem to be many answers THERE),

- you guess right, you cannot, you cannot twist NMEA cables either as nmea allows for only one talker on one line,

When I connect GPS / AIS to laptops I tend to separate them - then I can switch the AIS off but still use the GPS signal. Not sure if OpenCPN allows for this but I bet it should.

Let us know how it goes.

b.