OpenCPN and WiFi AIS

[LadyInBed]

I got round to tinkering with OpenCPN setup on my laptop, tablet and phone.
They all work well individually but only the first device that OpenCPN starts on picks up the AIS targets, the other devices don't show any targets.
If I just fire up two devices with OpenCPN then close the app on the device that is showing targets, the other device then starts showing targets (it doesn't matter which two devices).
Is that the case that the AIS engine WiFi will only talk to one device, is it a brand (em-trak) feature or do I have to set up the three devices with different parameters?
Has anyone got AIS WiFi talking to two devices at the same time, if so, how?

 

[RichardS]

Many wifi devices are limited by the manufacturer as to how many devices can connect to at once. I think my XB8000 AIS is limited to 5 devices connected at once but it sounds like yours is restricted to one.

Does your AIS offer TCP and UDP transmit options? You could try the UDP protocol.

Richard

 

[Elemental]

I think devices like that (some camera wifi's have similar restrictions) are often single connection constrained because they're using minimal stacks to reduce the load on the device. Your best route may be to consider using a device like a Pi/Openplotter combination to act as a relay and distribution hub for data and have your opencpn devices connect to that instead.

 

[Hoolie]

I think you might get more focused replies if you said which model of AIS Wifi you have.

 

[LadyInBed]

I think you might get more focused replies if you said which model of AIS Wifi you have.

Is that the case that the AIS engine WiFi will only talk to one device, is it a brand (em-trak) feature or do I have to set up the three devices with different parameters?

Sorry if that wasn't clear.

 

[LadyInBed]

Does your AIS offer TCP and UDP transmit options? You could try the UDP protocol.

Richard

Not that I can see, the only protocol options are in OpenCPN..

 

[Hoolie]

Sorry if that wasn't clear.[/COLOR]

em-trak appear to offer seven different types of AIS equipment, not including a splitter. It's very unlikely they all have the same software ... ...

 

[RichardS]

Not that I can see, the only protocol options are in OpenCPN..

I see. If the wifi transmitter only uses TCP then you are stuck with that I'm afraid. Usually the manual will state whether it will only support one client. You could email em-trak to see if there is a firmware upgrade available which might increase the number of clients.

Richard

 

[laika]

Usually the manual will state whether it will only support one client.

A quick look at the em-trak web site...there's no "manual" for their latest wifi-enabled product is just a blurb leaflet and the manual for the last gen one has a few paragraphs on wifi which effictively say "use the proais2 software to configure wifi to allow you to connect an app to it". Looks like they've bolted on a wireless chip as an afterthought and not bothered with the documentation. Given that, I wouldn't be surprised if they didn't bother with the firmware either.

So let's see how LadyInBed's mail to em-trak support goes. Maybe it's a fab product apart from the documentation.

The starting point for kplex was looking at a £400 nmea-to-wifi converter from a different manufacturer which supported "up to 1 tcp client" and thinking "£400? And they couldn't be bothered to write a concurrent tcp server?"

 

[Yngmar]

A quick look at the em-trak web site...there's no "manual" for their latest wifi-enabled product is just a blurb leaflet and the manual for the last gen one has a few paragraphs on wifi which effictively say "use the proais2 software to configure wifi to allow you to connect an app to it". Looks like they've bolted on a wireless chip as an afterthought and not bothered with the documentation. Given that, I wouldn't be surprised if they didn't bother with the firmware either.

So let's see how LadyInBed's mail to em-trak support goes. Maybe it's a fab product apart from the documentation.

The starting point for kplex was looking at a £400 nmea-to-wifi converter from a different manufacturer which supported "up to 1 tcp client" and thinking "£400? And they couldn't be bothered to write a concurrent tcp server?"

Every AIS transceiver that uses the ProAIS2 software configuration tool is actually internally the exact same hardware for the AIS daughterboard, manufactured by SRT. The sketched housing in their case study may look familiar to emtrak users, but it's almost every marine electronics manufacturer (Raymarine, digital yacht, Comar, etc.) that went with this approach, as the difficult and time-consuming part was the approval for radio licensing to a multitude of international government (read: slow acting) agencies. This of course makes it even more hilarious that the price difference between them is often several hundred buckazoids. Amusingly enough, only the Chinese (Matsutec/Huayang) developed their own hard- and software, primarily because they (initially) didn't give a damn about radio licensing, although now that their products have gained a reputation, they've retroactively acquired some.

So this means for additional information missing from the instruction manual for your SRT based (ProAIS2) product, simply download and read the instruction manual for any other. The Digital Yacht one for example mentions:

Normally if you select a TCP connection (single device) then you will have to enter both the IP address and Port, while if you select a UDP connection (multiple devices) you usually will only have to enter the Port number.

So this implies the device only supports a single TCP connection, but also does UDP broadcasts on port 2000. If you set your OpenCPN on the second (or all) device(s) to listen to that instead, you should get them all receiving AIS data.

 

[LadyInBed]

So let's see how LadyInBed's mail to em-trak support goes. Maybe it's a fab product apart from the documentation.

apart from documentation and support website!!
I have submitted a query to them after trying to use their FAQ link (which failed)

Please be aware that access to the product support articles contained within this site is restricted to authorised em-trak dealers and distributors. If you would like access to this site, then please contact us by clicking on the "Submit a request" button above.

If you are an end-user of our products, please be aware that answers to FAQs and access to useful downloads can be found at www.em-trak.com/em-trak-support/. No password / login is required to access the articles in the em-trak.com site.

Our Knowledge Base has changed

looks like they didn't change the link!

We have migrated to a newer version of the Knowledge Base.
All the articles have been ported over, however if you are unable to access any previous content or have noticed any discrepancies please contact us at support@em-trak.com

Now found FAQ's - on Dropbox!
https://www.dropbox.com/s/sx01g9sn4gp7s8c/B330.pdf?dl=0

 

[LadyInBed]

Got a reply from em-trak support
"We have been notified about this error and will be investigating it."

 

[peterf]

If you use TCP then it only provides a single connection.
Depending on the App changing from TCP to UDP might keep the TCP connection enabled and cause the same limitation of just one connection..

The recommended approach is to
1) Turn of AIS/Wifi equipment
2) Set all devices to communicate over UDP and possibly start /stop app to make absolutely sure not TCP connection remains open.
3) Turn on AIS/Wifi equipment

Once you've done this for the first time, subsequent connections should just work without following this process. ..

This is effectively what a digital yacht rep told me over email just morning when I also inquired about the same problem.. Unfortunately I'm not down at the boat for another week+ to check.. Would be interesting to hear if the advise works?



good luck.. Peter

 

[RichardS]

If you use TCP then it only provides a single connection.
Depending on the App changing from TCP to UDP might keep the TCP connection enabled and cause the same limitation of just one connection..

The recommended approach is to
1) Turn of AIS/Wifi equipment
2) Set all devices to communicate over UDP and possibly start /stop app to make absolutely sure not TCP connection remains open.
3) Turn on AIS/Wifi equipment

Once you've done this for the first time, subsequent connections should just work without following this process. ..

This is effectively what a digital yacht rep told me over email just morning when I also inquired about the same problem.. Unfortunately I'm not down at the boat for another week+ to check.. Would be interesting to hear if the advise works?



good luck.. Peter

I suggested this some time ago but I think the OP says that the em-trak can only use TCP and not UDP.

Richard

 

[LadyInBed]

I suggested this some time ago but I think the OP says that the em-trak can only use TCP and not UDP.

Richard

What I said was the only protocol options are in OpenCPN, and I have set it to UDP.
But em-trak support have acknowledged that it is a known issue which they are working on.

 

[RichardS]

What I said was the only protocol options are in OpenCPN, and I have set it to UDP.
But em-trak support have acknowledged that it is a known issue which they are working on.

I don't understand.

I suggested transmitting UDP rather than TCP and you came back and said that whereas OpenCPN can accept UDP, there is no option to transmit UDP by the AIS unit .... which means that you cannot use UDP.

I simply repeated your observation in my post #14 so I'm not sure why you now appear to be correcting me.

Richard

 

[LadyInBed]

I don't understand.

I suggested transmitting UDP rather than TCP and you came back and said that whereas OpenCPN can accept UDP, there is no option to transmit UDP by the AIS unit .... which means that you cannot use UDP.

I simply repeated your observation in my post #14 so I'm not sure why you now appear to be correcting me.

Richard

Sorry I wasn't clear, what I should have said was that there in no option to set the protocol in the ais box setup, so I don't know what it is.
I set OpenCPN to UDP on all three devises and each device connects and works ok individually but not together.