[CA] Adding STNG and N2K to exisiting Seatalk

[Chuck - Raymarine - Moderator]

Grant,

Q1. I will check with the owner on whether he needs/wants AIS on the bridge as well as the pilothouse. If not, then we can dedicate one of the C-120's NMEA port for the (2) VHF's as you suggested. I'd already thought of that, but if it were me I would not want to sacrifice AIS to get DSC.
A1. From the standpoint of access to AIS data via both MFDs, this is indeed subjective. Should the two MFDs be located at the same steering station, then it would typically be recommended that the NMEA 0183 AIS data source be interfaced the MFD which will primarily be used as the system's chartplotter. However, should the two MFDs be located at different stations, then it may be desirable to have access to AIS data at both stations.

Q2. Thanks for the pointer to the E70196. Looks a lot like an E22158. I'll look into adding this as an option. Is there some reason the instruction sheet/manual is not available for download?
A2. Please click here to view a FAQ addressing this subject. Raymarine's web master will be contacted to add any documentation for the E70196 posted with Raymarine's other Manuals and Documents. The E70196 is indeed nothing more than a E22158 which has a different cable (two leads) to support interfacing the ST-STng Converter to a 4800 BAUD NMEA 0183 listener requiring basic GPS data (VHF radio, SSB, etc.).

Q3. I also could find no mention of any prohibition to using two listeners with a single 0183-HS talker, including on the NMEA website. Is there a basis for this caution?
A3. While I too am not aware of any specification which prohibits splitting the of a 38400 BAUD output of an AIS receiver, it has been our experience that intermittent data communications may result. Accordingly, should you opt to move forward with interfacing both of the MFDs to the AIS receiver in the method proposed by your diagram, and should a problem persist, then it would accordingly be recommended that one of the MFDs be disconnected from the AIS data source.

Q4. Given that the GPS has now been identified as an RS125 and not an RS120 as originally thought, and that it will require it's own dedicated R52131 convertor.
A4. This unnecessary unless it is more convenient to interface the RS125 as shown. As the RS125 is designed to support SeaTalk communications and the present SeaTalk bus features only four devices, the RS125 may be added to the SeaTalk bus via the SeaTalk Auxiliary Junction Box, by adding another D244 SeaTalk Junction Block, using a terminal strip, etc.

Q5. Also - a new SanDisk 128MB CF card was purchased, and loaded in both C-120's for firmware update - they both ignored it and booted normally multiple times. Makes me wonder how these units ever got updated before now. Anyhow Rob at Radar Marine says he can't explain it either, all he knows is his cards work. I ordered one, we'll see.
A5. The results which you have specified are not atypical. While compatible CF memory cards were readily available during the period when the C-Series Classic MFDs were sold by Raymarine, they are far less common today. As Rob indicated, the CF memory card available through Radar Marine work quite well.

The new proposed diagram to include the following:

Q6. Second E22158 dedicated to Raystar RS125 GPS receiver.
A6. See the response to Q4.

Q7. E70196 to convert STng position data to provide 0183 position date to (2) VHF's @ 4,800.
A7. Correct

Q8. R55006 Junction box, to separate and cap off red power wires from C-120 MFD outputs, and combine data/ground conductors to a single SeaTalk output to D244 3-way junction block.
A8. Correct.

Q9. Please advise any potential issues with this setup as modified. Also - please advise approximate LEN or calculation method for legacy ST devices, when adding them to the STng network using the E21158's as shown. As the C-120's will not be connected to network power, my calculation shows just the two ST-60 Depth and the RS125 GPS as loads on the network.
A9. The location of your proposed power insertion spur should be adequate.