This interesting comment conversation has been pulled off the Simrad Go7 and B&G V7 entry, and I hope we can figure out if this is a standard or proprietary feature:
First impressions are good, apart from the lack of radar support. Page 88 of the Operator manual shows a nice user interface to support making DSC calls to an AIS target over NMEA 2000, complete with a change channel option. Not only that, it uses the standard N2K PGN 129808 so it works across brands.
NMEA 2000 using standard connectors and no NMEA 0183 connections!
Posted by: norse at March 31, 2015 8:31 PM | Reply
norse, let me add this:
NMEA2000 PGN 129808 signals an *incoming* DSC VHF call to, for example, a MFD - which can then display the location of the caller on the chart and/or show a notification message (I doubt that the latter has much use as the VHF radio is already ringing loud enough to wake the dead).
A standard NMEA2000 PGN for communication in the other direction, to instruct a VHF radio to set up an *outgoing* DSC call i.e. by using an MFD, is not yet defined. So Navico must do this via a proprietary PGN which won't be (can't be) supported by other manufacturers.
Not to take away from these nice features, though. It's the best Navico could have done given the blazing speed of NMEA.org to define new PGNs ;-) ... should I mention that the above PGN is still listed erroneously as "12808" on their web page and this hasn't been corrected for 5 years now?
Posted by: Henning at April 1, 2015 4:36 AM | Reply
On second thought: Maybe a standard PGN for an outgoing call has been defined and NMEA's website just hasn't been updated?
Does anyone know? Or knows how to get this information?
The GO7 manual, even though it has 122 pages, does not list supported PGNs.
Posted by: Henning at April 1, 2015 4:50 AM | Reply
Henning, look in the installation manual.
Posted by: Ben in reply to Henning at April 1, 2015 7:37 AM | Reply
OK, I did and it says
130842 SimNet DSC Message
The standard PGN numbers go up to 130578 (Vessel Speed Components) so I believe the range above are proprietary messages - including 130842.
Posted by: Henning at April 1, 2015 2:51 PM | Reply
Yes, I think you're right that the 1308xx range are proprietary PGNs, and it's an interesting bunch. My favorite mystery PGN = 130839 Pressure Insect Configuration ;-)
I doubt that NMEA's online PGN list is completely up to date...
...but also have not heard of a new PGN that handled DSC direct calling.
Posted by: Ben in reply to Henning at April 1, 2015 7:29 PM | Reply
The PGN list for the Go7 needs an edit check. There are several listed multiple times with different labels, which is odd. 130842 is one of these, however we know what that one really is, despite two misleading labels -- It is the proprietary PGN which enables AIS class B static data which Navico used at first. Now they use the standard PGNs of 129809 and 128810, although they still support 130842 for those who have the NAIS-300 transponder.
Since you probably won't take my word for it that 129808 is the proper PGN for DSC calls and that it works both ways, I'll have to find something definitive on the web. That's a bit tricky because it's a hard PGN to understand and there was a technical corrigendum to it in 2013 which isn't so easy to understand either.
Posted by: norse in reply to Henning at April 1, 2015 8:29 PM | Reply
OK, first of all, Kees has illustrated that Simrad proprietary PGN 130816 was used previously to make DSC calls from an MFD to a Simrad RS82/87 VHF.
Some documentation from NMEA you could look at is here:
Unfortunately, it implies that all DSC calls are distress calls. However, these fields
6 Proposed Rx Frequency/Channel
7 Proposed Tx Frequency/Channel
16 Calling Rx Frequency/Channel
17 Calling Tx Frequency/Channel
do imply that this PGN can be used both to set up a DSC call and report on a DSC call received.
and, the later information:
(it doesn't add to this discussion)
The bottom line is that Garmin has implemented the DSC call to an AIS target years ago and now Simrad can do it too (key point: over N2K using standard PGNs).
So it can be done, but how do they do it? The suspects are
PGN 129808, DSC Call Information.
PGN 129799, Radio Frequency/Mode/Power.
Posted by: norse at April 2, 2015 1:59 AM | Reply