Objective of NMEA
 

I am an NMEA neophyte. I am trying to connect my Raymarine speedo,
depth, and wind indicator. They use SeaTalk. Apparently, SeaTalk is
not NMEA language. I thought the point of NMEA was to make multiple
manufactures equipment communicate, much like MIDI (musical instrument
digital interface) works for electric guitars, keyboarsd, and
synthesizers.

I have a Garmin GPS, which does have some NMEA capabilities. I would
like to connect it to my ICom VHF, for the DSC feature. I would also
like to connect my sounder to the GPS to show depth on the Garmin. Is
this possible? Does anyone know where to get more information about
NMEA and connecting these various devices? I've already learned a bit,
but have a long way to go.

Also, from what I hear, the issue of "daisy chaining" is somewhat
resolved by the new NMEA 2000 protocol. Easy connectors, simple
wiring. Still, NMEA reminds me of DOS based computing. (it amazes me
that windows has DOS underlying it!)

I am sorry I bought my Ray Marine instruments that are not NMEA
compatible, if that's the word. Apparently, if I get a multiplexer, I
can make Sea Talk convert to NMEA. I'm sure all this junk is in it's
infancy, and one day will be resolved by some very cool technology.
It's already pretty cool, especially the Blue Tooth multiplexer made by
a company I don't know but recommended by someone on a google group.

anyone that cares to discuss this, I'm listening.

thanks

Luc

Objective of NMEA
 

I am an NMEA neophyte. I am trying to connect my Raymarine speedo,
depth, and wind indicator. They use SeaTalk. Apparently, SeaTalk is
not NMEA language. I thought the point of NMEA was to make multiple
manufactures equipment communicate, much like MIDI (musical instrument
digital interface) works for electric guitars, keyboarsd, and
synthesizers.

And much like MIDI, not everything works with everything else, especially
when combined. NMEA works well when there's not a lot of devices. There
are a number of multiplexing boxes available that can help manage multiple
talkers/listeners.

One point of SeaTalk was to get around the limits of NMEA.

Also, from what I hear, the issue of "daisy chaining" is somewhat
resolved by the new NMEA 2000 protocol. Easy connectors, simple
wiring.

The jury's still out on NMEA 2000 and it's actual standardization. It will
be a good thing when it does stabilize. Meanwhile, NMEA 0183 can be made to
work quite well.

Still, NMEA reminds me of DOS based computing. (it amazes me
that windows has DOS underlying it!)

Except it does, and hasn't since the days of NT and XP. Wake up.

I am sorry I bought my Ray Marine instruments that are not NMEA
compatible, if that's the word. Apparently, if I get a multiplexer, I
can make Sea Talk convert to NMEA.

Yep, you can gateway the signals to/from seatalk to NMEA.

I'm sure all this junk is in it's
infancy, and one day will be resolved by some very cool technology.

Meanwhile things like SeaTalk and NMEA 0183 get the job done pretty well.

It's already pretty cool, especially the Blue Tooth multiplexer made by
a company I don't know but recommended by someone on a google group.

Bluetooth, feh, I have no desire to leave my navigation data to the whims of
that crappy-ass protocol. I'll take a wired connection anyday, at least for
the important stuff.

Objective of NMEA
 

"luc" wrote in news:1141256143.930521.307560
@e56g2000cwe.googlegroups.com:

I am sorry I bought my Ray Marine instruments that are not NMEA
compatible, if that's the word.

Ah, let the hacking begin!
http://www.thomasknauf.de/seatalk.htm

There are many companies making Seatalk to NMEA converters, which are quite
pricey, of course. Just put:
Sealtalk to NMEA converter
into the Google search engine to smoke them out.

Conversion between Seatalk and NMEA on Lionheart takes place in the RL70CRC
radar/chartplotter display, which statements are controllable in the
display menus. Our main GPS is the Raymarine Seatalk Raystar 120:
http://www.raymarine.com/raymarine/P...ection=2&page=
80&product_id=144
The NMEA multiplexer feeds from the RL70CRC's NMEA output to the rest of
the boat's network.

Looking at the website, I notice they have whole new designed radomes to
replace our crappy 2D domes that rain inside and rot the potmetal guts.
Hope the new one is sealed up.

Objective of NMEA
 

Looking at the website, I notice they have whole new designed radomes to
replace our crappy 2D domes that rain inside and rot the potmetal guts.
Hope the new one is sealed up.

"Sealed up" being a theoretical state in the marine environment, of
course. Do the Raytheon open array antennas still have drain tubes to sling
water "in case" there should be any "condensation"? Hmmmmm?
Got about 12 liters of water out of an 8 foot Krupp Atlas one time. The
beautiful, almost new, 64 mile radar would only get echos from about half a
mile.
A good "TR down" installation had one or more mica "dams" in the
waveguide to keep from having wet feet in the pilot house (or the "void").
Old Chief Lynn

Objective of NMEA
 

The best place I've found for learning how to connect the devices is the
manufacturers web sites. If one of the devices is a Garmin, read what you
can get first, then verify with Garmin. They answer email within 24 hours,
and make the instructions simple and easy to follow. Connecting a DSC
capable radio should be easy. A depth finder may not have NMEA capability. I
wired my GPS to both a radio and a radar by splicing the wires to go to both
devices. You can also make a bus bar as a distribution point, with screws to
connect the wires.
"luc" wrote in message
oups.com...
I am an NMEA neophyte. I am trying to connect my Raymarine speedo,
depth, and wind indicator. They use SeaTalk. Apparently, SeaTalk is
not NMEA language. I thought the point of NMEA was to make multiple
manufactures equipment communicate, much like MIDI (musical instrument
digital interface) works for electric guitars, keyboarsd, and
synthesizers.

I have a Garmin GPS, which does have some NMEA capabilities. I would
like to connect it to my ICom VHF, for the DSC feature. I would also
like to connect my sounder to the GPS to show depth on the Garmin. Is
this possible? Does anyone know where to get more information about
NMEA and connecting these various devices? I've already learned a bit,
but have a long way to go.

Also, from what I hear, the issue of "daisy chaining" is somewhat
resolved by the new NMEA 2000 protocol. Easy connectors, simple
wiring. Still, NMEA reminds me of DOS based computing. (it amazes me
that windows has DOS underlying it!)

I am sorry I bought my Ray Marine instruments that are not NMEA
compatible, if that's the word. Apparently, if I get a multiplexer, I
can make Sea Talk convert to NMEA. I'm sure all this junk is in it's
infancy, and one day will be resolved by some very cool technology.
It's already pretty cool, especially the Blue Tooth multiplexer made by
a company I don't know but recommended by someone on a google group.

anyone that cares to discuss this, I'm listening.

thanks

Luc

Objective of NMEA
 

it's all pretty fubar, that's why it's hard to understand. :)

luc wrote:
I am an NMEA neophyte. I am trying to connect my Raymarine speedo,
depth, and wind indicator. They use SeaTalk. Apparently, SeaTalk is
not NMEA language. I thought the point of NMEA was to make multiple
manufactures equipment communicate, much like MIDI (musical instrument
digital interface) works for electric guitars, keyboarsd, and
synthesizers.

here's kind of the basics ...

NMEA ... depends on which standard you are talking about. there are
two, the NMEA 0183 standard which is a one way (one talker, many
listener) protocol for communicating GPS information from a GPS
receiver to one or more GPS data clients and a seperate NMEA 2000
protocol that is used for something more sophisticated. the NMEA 0183
protocol is sort of a language protocol, a series of text based
sentences, each one being a GPS fix, and the GPS receiver sends them
out on a periodic basis over 4800 baud. i don't think NMEA 0183 is a
hardware specification, however ... it's just a protocol, and it runs
over an rs-232 interface USUALLY, but it doesn't have to. it can also
be over USB, bluetooth, or whatever, the underlying hardware interface
as far as i know isn't specified. GPS receivers can put their GPS
information out on a serial cable in all kinds of formats, for example
my garmin i think has at least 10 different formats it can use. one of
those formats will be NMEA, usually, but some GPS receivers don't
support the NMEA format. that's all NMEA 0183, more about NMEA 2000
further down.

seatalk is a proprietary protocol and hardware specification created by
and for a manufacturer of marine equipment. it's not an open standard,
that is, as far as i know it's not published at all. it's kind of like
the ICOM CI-V protocol, it's just made by the manufacturer and they do
whatever they want with it to make their stuff work together. and they
charge a pretty penny to hook it all together, of course. seatalk is a
protocol that is used to transfer mostly sensor information such as
depth, wind speed, GPS information, etc, between instruments and
control equipment that talk it. at a hardware level it's also a
hardware spec which is basically rs-232 except that it's inverted ...
for god only knows what reason. a cynic might think they did it just
so it would be different than rs-232 and they could call it seatalk and
charge more, but i'm willing to give them the benefit of the doubt and
think they had a better reason. :)

NMEA 2000 is basically a network type of protocol like seatalk, except
it's an open standard that anyone can use. i haven't actually seen the
standard, but it's a protocol and a hardware specification, and i would
assume that it's very similar to rs-232 if not the exact same thing.
sort of the world's answer to a successful proprietary protocol when
the manufacturer is secretive and won't put out a specification for how
their stuff is hooked together. this is a bidirectional "networked"
type of protocol for transferring information like seatalk does around
different instruments and sensors.

I have a Garmin GPS, which does have some NMEA capabilities. I would
like to connect it to my ICom VHF, for the DSC feature. I would also
like to connect my sounder to the GPS to show depth on the Garmin. Is
this possible? Does anyone know where to get more information about
NMEA and connecting these various devices? I've already learned a bit,
but have a long way to go.

well, at a hardware level it's all pretty much rs-232, even seatalk
isn't that much different and can be converted, so you can learn a lot
about it just by reading about interfacing rs-232 devices together.
it's mostly just TX, RX, and ground wire(s), with sufficient attention
being paid to RF interference. at a software level i.e. the
communications protocol, that's a different animal altogether and
depends totally on what you are doing.

Also, from what I hear, the issue of "daisy chaining" is somewhat
resolved by the new NMEA 2000 protocol. Easy connectors, simple
wiring. Still, NMEA reminds me of DOS based computing. (it amazes me
that windows has DOS underlying it!)

if you mean it's very basic, it is, it's certainly not ethernet or
something like that. but you'd want it to be pretty basic. the
instruments aren't transferring very complicated data, it's all just
sensor readings and things. rs-232 is great for a lot of reasons, one
is that it's understood by a great many people, and another is that
it's fairly simple. it's also strong over longer cable lengths, easy
to interface to and make devices for, etc, and it's not that hard to
keep it from picking up distracting amounts of RF noise. so though it
isn't the most sophisticated way of doing things, maybe, it is pretty
hard to destroy and relatively easy to fix with available wiring.

in terms of development, rs-232 is much better than something
sophisticated like ethernet for these low bandwidth applications.
rs-232 is very simple and interfaces for it are even included in things
like PIC processors, very simple devices that are inexpensive to buy
and use. but as soon as you start wanting to talk ethernet then you're
talking about a TCP/IP stack, much higher bus speeds, some kind of a
basic operating system (typically), etc, you're going up a level in
sophistication and price. and you're also adding in a lot of potential
for failure as those devices get more sophisticated. there's something
to be said for being able to just grab some dumb terminal off the shelf
from like 1960 and hook it to your serial cable and see data coming
across it. :)

I am sorry I bought my Ray Marine instruments that are not NMEA
compatible, if that's the word. Apparently, if I get a multiplexer, I
can make Sea Talk convert to NMEA. I'm sure all this junk is in it's
infancy, and one day will be resolved by some very cool technology.
It's already pretty cool, especially the Blue Tooth multiplexer made by
a company I don't know but recommended by someone on a google group.

anyone that cares to discuss this, I'm listening.

thanks

Luc

Objective of NMEA
 

"luc" wrote in message
oups.com...
I am an NMEA neophyte. I am trying to connect my Raymarine speedo,
depth, and wind indicator. They use SeaTalk. Apparently, SeaTalk is
not NMEA language. I thought the point of NMEA was to make multiple
manufactures equipment communicate, much like MIDI (musical instrument
digital interface) works for electric guitars, keyboarsd, and
synthesizers.

I have a Garmin GPS, which does have some NMEA capabilities. I would
like to connect it to my ICom VHF, for the DSC feature. I would also
like to connect my sounder to the GPS to show depth on the Garmin. Is
this possible? Does anyone know where to get more information about
NMEA and connecting these various devices? I've already learned a bit,
but have a long way to go.

You could connect the NMEA output from the GPS to the NMEA input of the VHF
and at the same time connect the NMEA output from a sounder to the NMEA
input of the GPS.

If your sounder is part of the Raymarine setup, you can use one of my
multiplexers to convert Seatalk into NMEA.

Also, from what I hear, the issue of "daisy chaining" is somewhat
resolved by the new NMEA 2000 protocol. Easy connectors, simple
wiring. Still, NMEA reminds me of DOS based computing. (it amazes me
that windows has DOS underlying it!)

NMEA2000 is not a daisy chain, it is a similar setup like an ethernet
network where every device can send it's data on the network and listen to
any data on the network. A collision detection mechanism prevents data
corruption when two devices want to talk at the same time. It is based on
CAN.

Meindert

Objective of NMEA
 

"Bill Kearney" wrote in message
...
Bluetooth, feh, I have no desire to leave my navigation data to the whims
of
that crappy-ass protocol. I'll take a wired connection anyday, at least
for
the important stuff.

What exactly is crappy-ass about Bluetooth? We have a Bluetooth enabled
multiplexer and it works very well, just as reliable as a wire as long as
you are within the radio range.Even pilots are changing to Bluetooth
connections between the pilot-plug and their laptops, which enables them to
go anywhere on the ships' bridge.

Meindert

Objective of NMEA
 

"purple_stars" wrote in message
oups.com...
it's all pretty fubar, that's why it's hard to understand. :)

That is obvous...

With all respect Luc, but you're mixing things up very badly in your attempt
to explain things.
I'll comment between the lines:

The NMEA 0183 protocol is sort of a language protocol, a series of text
based
sentences, each one being a GPS fix, and the GPS receiver sends them
out on a periodic basis over 4800 baud. i don't think NMEA 0183 is a
hardware specification, however ... it's just a protocol, and it runs
over an rs-232 interface USUALLY

No. NMEA 0183 is a protocol AND a hardware specification, which exactly
specifies the voltage levels and the number of interface wires too. The
hardware side is the same as RS-422.
Any device with an RS232 port is not compliant with the NMEA-0183 standard
and is as such even forbidden on commercial vessels sailing under SOLAS
rules.

A GPS with an RS-232 interface will output NMEa formatted sentences but it
is stricktly speaking not an NMEA interface. The problem is that many
manufacturers choose to deviate from the standard in order to make a cheap
computer interface.

Seatalk is a proprietary protocol and hardware specification created by
and for a manufacturer of marine equipment.

Seatalk is a hardware AND a protocol (messages) specification which is
completely different from NMEA and RS-232 or RS-422. It is a one-wire
multiple-access collision detect protocol and indeed proprietary.

it's not an open standard,
that is, as far as i know it's not published at all. it's kind of like
the ICOM CI-V protocol, it's just made by the manufacturer and they do
whatever they want with it to make their stuff work together. and they
charge a pretty penny to hook it all together, of course. seatalk is a
protocol that is used to transfer mostly sensor information such as
depth, wind speed, GPS information, etc, between instruments and
control equipment that talk it. at a hardware level it's also a
hardware spec which is basically rs-232 except that it's inverted ...

Not at all. The only resemblence with "RS-232" is that it is serial data.
RS-232 is no protocol spec either, it just specifies the signals and their
levels on a connector. And an RS-232 link is meant to be a point-to-point
connection between two devices only.
Seatalk works on different levels AND it has 9 bits per byte while your
ordinary serial computer port can only handle 8 bits per byte (there are
some unreliable workarounds...).

for god only knows what reason. a cynic might think they did it just
so it would be different than rs-232 and they could call it seatalk and
charge more, but i'm willing to give them the benefit of the doubt and
think they had a better reason. :)

There is a better reason in the fact that it is a multiple-access collision
detect protocol which simply means that you can connect more than one device
on a line and they can all talk and listen.

NMEA 2000 is basically a network type of protocol like seatalk, except
it's an open standard that anyone can use. i haven't actually seen the
standard, but it's a protocol and a hardware specification, and i would
assume that it's very similar to rs-232 if not the exact same thing.

NMEA 2000 is far far away from RS-232. Like I said earlier, RS-232 is only
for point-to-point connections while NMEA 2000 (CAN based) is a network for
multiple devices. The standard is open but you have to pay around $10,500
for the documents, test suites and manufacturer/product codes.

Meindert

Objective of NMEA
 

"purple_stars" wrote in message
ups.com...

yeah i looked it up, nmea 2000 is using CAN (controller area network).
it's basically a juiced up rs-232 type of interface, a serial interface
capable of higher speeds and has some addressing in it. from a
development point of view circuits just replace their serial UART with
a CAN interface device and go about their business, with some added
software complexity. anyway ... whatever ... it's still a very simple
interface with simple wiring, TX and RX, and you're still going to have
pay attention to RFI, same as rs-232.

The above should be ignored because it is utter nonsense. Sorry to say it
this way but that's how it is.

Meindert