Plug-in to Parse Proprietary Raymarine SeaTalkHS?

[Beausoleil]

Is there any interest out there in integrating Raymarine's proprietary IP-over-Ethernet SeaTalkHS data into OpenCPN?

I'm pretty busy right now, but I could grab some Wireshark captures of data on my network as a start to anyone who's interested.

Raymarine's very closed-minded about it, but I assume that it's mostly UDP based info which is broadcast to a specific multicast group ID. Right now the only devices on my Raymarine ethernet are an E-120 Classic chartplotter and their DSM-300 digital fishfinder. I'd like to at least capture a network "announcement" when the E-120 boots, and a "join" when the DSM is powered up. If I had a legal copy of RNS, their PC chartplotting software, I'd capture that also. I know you can download a working demo copy, but I don't thing the IP/Ethernet functionality is enabled...

[idpnd]

Don't they have NMEA output? My aged raymarine stuff does

[Beausoleil]

Originally Posted by idpnd

Don't they have NMEA output? My aged raymarine stuff does

Yes, they have NMEA, but on my E120 "Classic" MFD, there's only one and it's the only interface to which you can connect an AIS unit. And the other catch is that the only interface over which the E120 will forward AIS info is over their proprietary ethernet interface - HSB2. They don't forward it over the NMEA2000/Seatalkng port.

So, to share AIS data between my PC running OpenCPN, I'd need an NMEA multiplexer with two high-speed ports (38.4kb/s), or the better option would be a plug-in which could read all data over the HSB2 ethernet interface.

It's IP, so in theory it's doable. Just join the E120's UDP multicast group, and interpret the data coming in. I hope to have time this fall to start such a project, but right now I'm up to my ears in other projects...

[HamishB]

fwiw it's easy enough to build a NMEA Y-cable splitter, you just need to splice into the transmit and ground wires. (as long as cable runs are not too long)

Hamish

[malcolmh]

Be careful not to confuse SeaTalkHD with SeaTalkNG. SeaTalkNG is NMEA2000 with proprietary connectors and is used for all the usual NMEA data transfers (GPS, depth, etc), whereas SeaTalkHS is used to transfer graphical information like radar or fish finder pictures.

[Beausoleil]

Originally Posted by malcolmh

Be careful not to confuse SeaTalkHD with SeaTalkNG. SeaTalkNG is NMEA2000 with proprietary connectors and is used for all the usual NMEA data transfers (GPS, depth, etc), whereas SeaTalkHS is used to transfer graphical information like radar or fish finder pictures.

No confusion here.

Raymarine's high-speed Ethernet protocol was alternately referred to as HSB2 or SeaTalkhs. SeaTalkhs is not only used for graphical information - it also supports transfer of all data which can be transported by any other Raymarine-supported interface: NMEA 0183, SeaTalk, SeaTalk2 (aka SeaTalkNG).

Regarding HamishB's recommendation about an NMEA splitter: NMEA0183 did not officially support more than one talker on a single "network", but it sometimes worked. In my opinion, with the data rate bumped up to 38.4kbit/s from the original 4.8kbit/s, the chances of data collisions are much higher, and because of cable run lengths in my case of 30+ feet, I'd rather try a more robust approach by using the Ethernet interface. I guess I could experiment with it, but I think more people could benefit from a plug-in which supports SeaTalkhs...