DSC emergency Alerts

chtucker

Furuno Fan
Twice now I have received DSC emergency alerts on NMEA2000 Lowrance Link 8 VHF. The alerts have not indicated on my TZT9 running 3.01 I know the Link 8 is functioning on the network as I see it's AIS reception on the plotter and the VHF is displaying the NMEA2000 GPS position.

I haven't tried a DSC non emergency call to see what happens as I don't have a radio programmed with a different MMSI than my own. Does anyone have experience with DSC message reception in the TZT?

On a side note, it would be "nice" if I could make a DSC call from an MMSI that received/displayed from the AIS. Is this a possibility or not in the NMEA protocol?
 
Good morning CHtucker,

Next time you receive a DSC alert or message trying viewing the message in the DSC list that can be found by pushing the "home" button then choose list. You can choose what list to view by choosing the appropriate option, try the "DSC" list. Below is an excerpt from the TZT operators manual.

If you have a friend or dock-mate that has a DSC radio you can test this feature out by sending a non-alert message to a specific MMSI. Have your friend send you a position report via DSC, that should register on your TZT display.

If you get an MMSI number via an AIS target you can use that MMSI number to make a DSC call to that specific MMSI number via your DSC radio. You will want to make a "routine call" which is non emergency.

DSC List.PNG
 
I had a similar issue and called the Furuno tech support line. What I was told is that the TZT will not display a regular DSC call alert. It will only display a DSC position request. I have a handlheld HHF with a different MMSI than my boat's VHF and was able to confirm that this is indeed the case. When I used the handlheld to make a routine call to the boat, the DSC alert sounded on the VHF but the TZT did not indicate a DSC call or show a target. Then I tried using the handheld to send a position request to the boat VHF and sure enough, the handheld MMSI showed up as a target on the TZT.
 
Following up on this after I updated my Lowrance radio.

Page 29 of the TZT manual, section 1.21 indicates that the DSC information must be output by the VHF radio on NMEA0183, The TZT does not have any NMEA0183.

So what is the correct way to get DSC info into the TZT network? The VHF radio does have NMEA 0183 and I could add a converter..

What DSC PGNs does the TZT recognize?e
 
Good afternoon chtucker,

Thank you for the information. The TZT as you know is only NMEA2000, if your VHF DSC radio is only NMEA0183 you will need to use a NMEA2000/NMEA0183 converter. The IF-NMEA2k2 would be a good choice because it will translate both the DSC and DSE messages from you radio to NMEA2000 PGN129808. The TZT14 will also look at PGN129808 for DSC and DSE information. Please note that not all radios output the DSE message which carries additional DSC information.

Couple other additional notes, you will want to make sure that your TZT is using the latest version of software. Also confirm that the following is turned on in the Menu: Menu-Targets-Display Target IDs is set to “ON”.
 
Will do! I left the boat for a week to visit family, but will troubleshoot later this week. I have received mixed responses back from Lowrance which complicates the matter.

I will update the TZT to 4.x (don't recall the latest version) I am currently at 3.12 as it has been stable.

Surely it would be simple to use the N2K from the Lowrance radio, but if needed I will add the N2K converter to my second radio which is 0183 only.

Has the TZT been tested with the Furuno FM8900S and the NMEA 2000 converter? I might go that route if I replace the Lowrance (which has performed poorly, but has a lot of features)
 
Good morning chtucker,

I have not personally tested that combination of equipment with a TZT unit using an IF-NMEA2k2. I can tell you the FM8900 is an IMO type approved VHF radio and supports all DSC functionality with accordance to SOLAS Regs. IV/6.3, 7.1.1, 8.2.
 
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