May I place DSC call through chartplotter AIS target?

[olddog57]

I posted this at another thread (about cheapest AIS transponder), then decided to have a separate thread.

I have Standard Horizon DSC-VHF (with AIS receiver built in), and I have an Axiom chartplotter.
It is very easy to initiate a DSC call to an AIS target with the above VHF, but should I install an AIS transponder and connect it to the Axiom - will I be able to connect to these the VHF and then to place DSC calls on AIS target through the Axiom? Which , if possible, should be more convenient than through the VHF with its small screen).

I should add, the VHF only has the NMEA 0183 interface, while bith Axiom and AIS have NMEA 0183 & NMEA 2000

[maine50]

please verify the Axiom (nor axiom pro) has nmea 183 capability. I believe the ones at least in the last few years do not.

[Dsanduril]

The short answer is probably not. There are two standard DSC sentences in NMEA 0183; DSC and DSE. These generally are used to send data from the radio to your chartplotter. Your chartplotter (if it understands these sentences) can display the source and position of a DSC call coming in, particularly if it is a DSC distress call.

In NMEA 0183 (and even NMEA 2000) there isn't much in the way of initiating a DSC call from the chartplotter. This is a desirable function and some vendors have it available, but generally as a proprietary sentence(s). So, if you have a Raymarine chartplotter you might be able to control a Raymarine radio. Same for B&G. But the odds of some unknown AIS, feeding a Raymarine Axiom, and then dialing an SH VHF radio are pretty slim (I do know there are some people who have hacked together interoperability for some systems, but those solutions are very specific).

An article on this subject from CF's continuouswave:

https://continuouswave.com/whaler/re...rtPlotter.html

[smac999]

why are you calling boats with DSC? just hail them on the local calling channel by getting the name off the ais. most boat owners don't know how to use DSC. and will just get mad when the vhf starts beeping. it's a dumb system that was never needed to be invented.


if you want to tryit I would just leave the ais transponder separate to transmit. and hook up the standard horzion to the plotter to give ais (why was this not already done?) and plotter to vhf. only the pro has nmea 183 though.

generally you need same brand plotter / vhf to make the dsc funtions work though.

[olddog57]

Originally Posted by maine50

please verify the Axiom (nor axiom pro) has nmea 183 capability. I believe the ones at least in the last few years do not.

Thx, you're right: mine only has NMEA 2000

[olddog57]

Originally Posted by Dsanduril

The short answer is probably not. There are two standard DSC sentences in NMEA 0183; DSC and DSE. These generally are used to send data from the radio to your chartplotter. Your chartplotter (if it understands these sentences) can display the source and position of a DSC call coming in, particularly if it is a DSC distress call.

In NMEA 0183 (and even NMEA 2000) there isn't much in the way of initiating a DSC call from the chartplotter. This is a desirable function and some vendors have it available, but generally as a proprietary sentence(s). So, if you have a Raymarine chartplotter you might be able to control a Raymarine radio. Same for B&G. But the odds of some unknown AIS, feeding a Raymarine Axiom, and then dialing an SH VHF radio are pretty slim (I do know there are some people who have hacked together interoperability for some systems, but those solutions are very specific).

An article on this subject from CF's continuouswave:

https://continuouswave.com/whaler/re...rtPlotter.html

Thank you, it's clear enough now.
Well, my VHF-AIS still permits to place DSC call straight on AIS target

[olddog57]

Originally Posted by smac999

why are you calling boats with DSC? just hail them on the local calling channel by getting the name off the ais. most boat owners don't know how to use DSC. and will just get mad when the vhf starts beeping. it's a dumb system that was never needed to be invented.


if you want to tryit I would just leave the ais transponder separate to transmit. and hook up the standard horzion to the plotter to give ais (why was this not already done?) and plotter to vhf. only the pro has nmea 183 though.

generally you need same brand plotter / vhf to make the dsc funtions work though.

U r right, mine lacks nmea 183, I found this only today.
Regarding the DSC calls: that's mostly for calling big ship in situations unclear

[muttnik]

Originally Posted by olddog57

will I be able to connect to these the VHF and then to place DSC calls on AIS target through the Axiom?

Curiously this is something I was investigating only a couple of weeks ago and the answer to that particular question (which I asked of Raymarine) is "No, but there's a feature request in for it and they recognise the desirability for that not to be a proprietary mechanism which only works with Raymarine radios".

The more interesting thing is how this works in the rest of the market. You can place calls from a navico plotter to a navico radio, from a garmin plotter to a garmin radio (N2K only) and from an ICOM or Vesper AIS with a screen (e.g. watchmate 850) to an ICOM radio (NMEA-0183 only). Other combinations may be possible (post what you know :-)

Finding out *how* this works is another question as support folk often don't know details.

Navico ignored my enquiry as it seems they frequently do.
Garmin said they used only standard rather than proprietary mechanisms. Initially they said calls were initiated by PGN 129808 (which I believe is used for DSC notifications radio->plotter per the -0183 DSC sentence). When I pointed out that the plotter manual said that 129808 was receive only (ie not tx) they revised this to PGN 129799, but that does not seem to have the required fields so I'm not really sure I have an answer there.

ICOM initially told me call initiation was via a proprietary sentence but when I pointed out that Vesper AIS units could initiate calls with their radios they seemed less sure. Vesper told me they used an ICOM proprietary sentence. This would seem an odd choice if the DSC sentence could already be used to make a call (as suggested by continuouswave's analysis referenced by Dsanduril above)

I would be great if someone with a vesper or ICOM AIS could test this out by tapping into the NMEA out of the AIS (the 4800 port of icom ma-5x0tr or the watchmate with output set to 4800) and connecting to a computer, making a DSC call from the AIS unit and seeing what sentences were produced.

Also be interesting if someone with a Garmin plotter and ability to snoop n2k pgns could do the same

[olddog57]

Thank you for your input: it is clear now: the possibility we want is virtually non existent meanwhile.
Well, the VHF/AIS receiver still can be used.

[JasonS]

We have an Axiom Chartplotter and Vesper Cortex AIS/VHF.

One button push to call any target. Works great.

[sailjumanji]

As an earlier poster also said, I have DSC called large ships several times to establish a passing protocol in a ship channel. (Basically in a situation that you would think they would answer.) Have never got an answer to the DSC. However when I call them by name on VHF, have always gotten an answer. So I don't mess with DSC anymore.

Also can tell you from experience that the call target button on the B&G Zeus 3 hooked up to Vesper 8000 XB and Icom VHF via N2K, does not work. The B&G sentence is not in a format recognized by Icom.

[olddog57]

Originally Posted by JasonS

We have an Axiom Chartplotter and Vesper Cortex AIS/VHF.

One button push to call any target. Works great.

That seem to be one of not too many solutions, but priced at about €2K - thank you very much, I'll stay out of it.

[muttnik]

Originally Posted by sailjumanji

Also can tell you from experience that the call target button on the B&G Zeus 3 hooked up to Vesper 8000 XB and Icom VHF via N2K, does not work.

Per my earlier post, the ICOM only accepts call setup over nmea-0183. This includes between their own n2k-enabled devices the MA-510TR and the M605 (info from asking ICOM UK support).

Originally Posted by muttnik

ICOM initially told me call initiation was via a proprietary sentence but when I pointed out that Vesper AIS units could initiate calls with their radios they seemed less sure. Vesper told me they used an ICOM proprietary sentence. This would seem an odd choice if the DSC sentence could already be used to make a call (as suggested by continuouswave's analysis referenced by Dsanduril above)

Looking at both the vesper and ICOM AIS manuals, "DSC" is listed as a *transmitted* sentence. The only thing I can think an AIS receiver would be transmitting a DSC sentence for would be call setup lending weight to the DSC rather than proprietary sentence theory (unless anyone can think of another reason the AIS unit might be transmitting a DSC sentence?).

It would be great if someone with a watchmate with a screen or the icom AIS unit could test this out. Once we know how it works it'd be a great feature to add to OpenCPN.

[continuouswave]

The general topics here are:

--Can a DSC radio set-up a DSC call based on input to the radio via NMEA-0183 using a standard sentence?

and

--Can a DSC radio set-up a DSC call based on input to the radio via NMEA-2000 using a standard parameter group (PGN)?

I have not see definitive proof or an actual example of either of those features in any DSC radios. As mentioned by others, however, it appears that there are certain combinations of DSC radio and multi-function display or chart plotter devices that can produce a DSC radio call set-up by a message sent to the radio from the chart plotter, with the provision that both radio and chart plotter were made by the same manufacturer. The implication is that the data sent to the radio is NOT in a standard PGN or in a standard sentence.

If there is a standard NMEA-0183 sentence that will cause a DSC radio to set-up a DSC call, I would very much like to see the content of that sentence and a description of the sentence. As mentioned above, I generally have see a DSC radio OUTPUT sentences named DSC and DSE. I have not observed any chart plotter communicating with a DSC radio using those same DSC and DSE sentences as INPUT to the radio. If this can be done, and someone is doing it, I would like to hear about it and see the contents of the sentence being sent to the radio to set-up the call.

As I have mentioned before, the operation of a DSC radio is REQUIRED to conform to strict behaviors with making radio transmissions to other DSC radios or when receiving radio transmissions from other DSC radios, but as far as I can tell, there are not specific required behaviors for the radio to respond to input of data from a connected device using NMEA-0183 or NMEA-2000 to be able to set-up a DSC call.

As others have inferred or perhaps observed, the call set-up function seems to always rely on using a proprietary sentence or PGN.

[sailjumanji]

The B&G Zeus chartplotter combined with a B&G VHF on a NMEA 2000 system is advertised to make a DSC call to an AIS target with just the press of a button on the AIS popup. Its in the owners manual. I tried doing same with a Zeus 3 and ICOM 506, and it didn't work. B&G tech told me its because B&G uses proprietary - or specific to their equipment only - sentence to place the call. It was NOT because we were using NMEA 2000 instead of 183.

So apparently if you go B&G combination this works. Im not a fan of B&G VHF, so cant. That said, ive tried reaching bridge of ships using DSC maybe a half dozen time, and none answered. ALL of them answered subsequent hails by name over VHF. So i put low importance on DSC call of AIS tsrget.