NEMA In, NEMA Out.....

[beetlejuice30]

i have a few questions about NEMA
So does a NEMA Out from my VHF connect to my NEMA In on my chartplotter?
and my NEMA out Connect to my NEMA In on my class D-DSC VHF?

and if i had a AIS can i just hook that on the same NEMA In that the vhf it hooked to on my chartplotter?
can i hook my sailing gauges to my chartplotter threw NEMA as well?

Chartplotter raymarine RL70c+
VHF standard horizon class D-dsc
AIS transceiver Class B
Sailing gauges data marine (older)
can all this communicate threw one set of NEMA in and out

autopilot raymarine X-5 communicating threw seatalk
raymarine 4k radar dome

thank you in advance for your help
Beetle

[beetlejuice30]

Oops NMEA

My bad

[Captain Bill]

The NMEA 0183 interface is pretty much 1 talker to one listener without a multiplexer. There is a pretty good discussion of how it works at the actisense web site. Downloads specifically the one titled "A collection of very useful information about NMEA 0183 (v2.00)".

[Maren]

Originally Posted by Captain Bill

The NMEA 0183 interface is pretty much 1 talker to one listener without a multiplexer. There is a pretty good discussion of how it works at the actisense web site. Downloads specifically the one titled "A collection of very useful information about NMEA 0183 (v2.00)".

Bill brings up a good point which begs the question of whether you are referring to NMEA 0183, NMEA 2000 (aka N2K) or a combination of both.

[richardhula]

Originally Posted by beetlejuice30

i have a few questions about NEMA
So does a NEMA Out from my VHF connect to my NEMA In on my chartplotter?
and my NEMA out Connect to my NEMA In on my class D-DSC VHF?

and if i had a AIS can i just hook that on the same NEMA In that the vhf it hooked to on my chartplotter?
can i hook my sailing gauges to my chartplotter threw NEMA as well?

Chartplotter raymarine RL70c+
VHF standard horizon class D-dsc
AIS transceiver Class B
Sailing gauges data marine (older)
can all this communicate threw one set of NEMA in and out

autopilot raymarine X-5 communicating threw seatalk
raymarine 4k radar dome

thank you in advance for your help
Beetle

Hi Beetle - the NMEA input on your DSC VHF radio is to allow it to have GPS position which can be used by it when sending a digital distress message.

The NMEA output from same device gives distress messages which can be interpreted & displayed by a suitable charplotter. I know this works on Raymarine C/E series but maybe not the RL70.

NMEA instrument data can either be fed to a chartplotter seperately or multiplexed with GPS NMEA to provide combined feed. The default speed for all above is 4800 baud, although many non-marine USB GPS receivers operate at 9600 baud or higher so beware.

AIS receivers/transponders only work with NMEA at 38400 baud. In a busy area there is potentially too much data to allow operation at lower speeds.

There are multiplexers that will accept mixed speeds & output at 38400 baud such that you can have one feed with all four of above sources, however you will need a chartplotter (dedicated or PC based) that is capable of displaying all this data. Failing that software or hardware solutions are available to allow separate feeds via COM ports.

Regards

[beetlejuice30]

couldn't say just trying to rap my head around it
its all new to me
let you know after i read the download
NMEA 0183 or NMEA2000
is one more recent then the other

[Captain Bill]

NMEA 2000 is the more recent

[beetlejuice30]

they should all be NMEA 0183

[scotte]

I'm a fan of Brookhouse NMEA Muxes, and have had great success with their products as far as integrating everything together. In my case I have a mix of NMEA 0183 and SeaTalk, with a Raymarine C-series. Brookhouse has a MUX designed for just this sort of setup - which handles rate conversion so that the C-series can operate at 38400bps for AIS/computer output but still integrate with NEMA 0183 and 4800bps.

For my particular setup, this worked great. I know you don't have a C-Series, but you should be able to integrate everything together, as long as it's not something like NMEA 2000...

I'm just a customer, but happy with their products and excellent support.

[beetlejuice30]

thanks for the input

i just found out that my RL70c+ will not display AIS or DSC distress call,
so that more or less makes my question a little mote but i do have macENC on my computer that does display AIS but doesn't do me much good by the helm, then i would have to get a NMEA to USB conversion box anyway so i'll keep that brand in mind thanks
i think i just hook my auto pilot threw seatalk and VHF thew NMEA and not worry about the wind indicator and such
and someday get AIS on my computer or upgrade to a c or e series

[fairbank56]

Originally Posted by Captain Bill

The NMEA 0183 interface is pretty much 1 talker to one listener without a multiplexer.

According to the NMEA standards, "Multiple LISTENERs may be connected to a single TALKER." In my experience, one talker can generally drive 3-4 listeners with no problem.

Eric

[Captain Bill]

Fairbank56, You're correct, a poor choice of words on my part. I was reacting to his proposal to connect two talkers to the same listener. I should have said only one talker can be connected to a listener. Since the talker assumes that it has a dedicated connection, it can and will walk on any other talkers.

[David M]

You can connect multiple NMEA talkers (sources) to one NMEA device with an input port (listener) but you will need a multiplexer in between the talkers and the listener. The talkers must connect each to their own unique terminal on the multiplexer.

A NMEA circuit is one way communication only. You need a separate NMEA circuit if you want NMEA sentences to go the opposite direction.

There is a limit to how many listeners can listen to a talker. As you increase listeners, eventually the voltage will drop so much that one or more listeners will not be able to "hear" the NMEA sentences. If this happens you will need a multiplexer to amplify the NMEA sentences.

There is also a limit to the number of sentences you can put on one NMEA circuit. Since it is a relatively high number for a pleasure boat, most people here don't need to worry about it.

[richardhula]

Originally Posted by David M

A NMEA circuit is one way communication only. You need a separate NMEA circuit if you want NMEA sentences to go the opposite direction.

True but a single cable could provide this, i.e. connecting to COM port on laptop with db-9 plug (via USB adaptor or direct) pin 2 NMEA+ in, pin 3 NMEA+ out, pin 5 common-.

There is a limit to how many listeners can listen to a talker. As you increase listeners, eventually the voltage will drop so much that one or more listeners will not be able to "hear" the NMEA sentences. If this happens you will need a multiplexer to amplify the NMEA sentences.

True again but in practice it's dependant on the working impedance of each device connected & is therefore difficult to predict. For the record I have had six physical devices connected to one GPS without a glitch. In most cases therefore it's not an issue.

There is also a limit to the number of sentences you can put on one NMEA circuit. Since it is a relatively high number for a pleasure boat, most people here don't need to worry about it.

Very true especially if it's high speed NMEA as with AIS distribution. Very unlikely in this day and age that any buffers will overflow.

Note NMEA 2000 is not the same as NMEA 0183 even at 38400 baud. NMEA 0183 sentences generally use three upper case alpha characters to define the data type they are sending, preceeded by two alpha characters corresponding to the source, making it easy to read "raw". NMEA 2000 uses six numerical characters to define the data type and the sentences are know as PGN's, hence need for a converter.

Regards

[Joli]

We use ShipModul Marine Electronics with a usb connection to the laptop. Works a treat, no complaints.