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Soonersailor, read the site listed in the beginning of the thread regarding how SeaTalk works. It will give you an idea of how this type of network is transporting information, as well as its limitations. It's pretty cool, once you get it. NMEA can ONLY send or receive these strings of data. That's why you have NMEA input positive and output positives, plus the accompanying negative wires. Add a 12 volt power wire, and the software to process stuff in two directions, and you have Seatalk. It was a pretty clever idea in its day. Then came ethernet cable and that was the advent of the high speed network. Then, along came the later network of a single cable with junction nodes called Seatalk ng (for next generation). This is evolution in action.
Regarding the use of a single buss terminal as a distribution node for NMEA 0183, it's probably not discovery on my part, I simply observed that an NMEA 0183 device that is outputting data doesn't need to coordinate its data with the stream from other units doing the same. Information either slips into the line of data, or it crashes into another sentence, thus negating the two pieces of data for a millisecond until the next pieces fall into sync. Same for a device reading (input of data) the stream of sentences. If it is programmed to accept only the info for water depth or wind angle, only that info gets shown on the display. So, I tried it, dumping NMEA 0183 outputs into a terminal buss, and wiring the inputs into the same buss. Think of it as plumbing with one way valves and a big manifold. It has limited use, but it seems to work fine.
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