Moderated Discussion Areas
  ContinuousWave: Small Boat Electrical
  Connecting GPS Receiver to Marine Radio

Post New Topic  Post Reply
search | FAQ | profile | register | author help

Author Topic:   Connecting GPS Receiver to Marine Radio
Waccamaw Whaler posted 05-29-2009 11:33 PM ET (US)   Profile for Waccamaw Whaler   Send Email to Waccamaw Whaler  
I sense I'm making this more difficult than it really is. I'm about to connect my Standard Horizon PS1000 marine radio to my Garmin 545S GPS receiver so the Maritime Mobile Service Identy [MMSI] is functional.

Do I simply connect the blue to blue wire and the black (GRD) to green wire as shown on the one attachment? All of the applicable documents to each piece of equipment are attached.

What is the best way to connect these 'tiny' wires? I can solder them but I'm not certain shrink wrap is available that small. I don't want to have to use a terminal block because of the difficulty mounting because of all the other wires and the confined space inside the console. MMSI%20Garmin%20to%20Standard%20Horizon/

jimh posted 05-30-2009 07:45 AM ET (US)     Profile for jimh  Send Email to jimh     
It would be quite a coincidence if the connection happened to work out so the same color wires were used for the signals. I think this is a typical misunderstanding by boaters.

You are making a serial data connection between two devices. The GPS receiver is the sender of data; the radio transmitter is the listener. Connect the output from the receiver to the input of the transmitter. The instruction book will tell you the wire colors in each case.

Waccamaw Whaler posted 05-30-2009 05:40 PM ET (US)     Profile for Waccamaw Whaler  Send Email to Waccamaw Whaler     
Jim please look at my attachment. Am I interpreting the instructions correctly i.e.,

Blue to blue wire and the black (GRD) to green wire

I 'think' this is what you are telling me?


jimh posted 05-30-2009 08:02 PM ET (US)     Profile for jimh  Send Email to jimh     
Ron--Hook the output to the input. If you want to list the colors here, I will help you.
jimh posted 05-30-2009 08:04 PM ET (US)     Profile for jimh  Send Email to jimh     
The MMSI is the Marine Mobile Service Identity. You enter this via the control panel of the radio. You don't need any sort of interconnection of radio and other device to enter the MMSI.
jimh posted 05-30-2009 08:22 PM ET (US)     Profile for jimh  Send Email to jimh     
Ron--It looks to me like your "attachments" are only about one device. Locate the information for both devices. Transcribe it here, giving the signal and the color code.
Waccamaw Whaler posted 05-30-2009 09:46 PM ET (US)     Profile for Waccamaw Whaler  Send Email to Waccamaw Whaler     
[Removed long cut and paste which did not survive the text formatting.]
jimh posted 05-31-2009 01:40 AM ET (US)     Profile for jimh  Send Email to jimh     
Ron--Just tell me the signals from the GPS receiver and their wire colors. Then tell me the inputs to the radio and their wire colors.

Let me give you an example:

NMEA output (+) = COLOR
NMEA ground = COLOR

NMEA input (non-inverting) = COLOR
NMEA input (inverting) = COLOR

Just fill in the colors. Don't cut-and-paste a page of text.

Waccamaw Whaler posted 05-31-2009 02:22 PM ET (US)     Profile for Waccamaw Whaler  Send Email to Waccamaw Whaler     
Jim, I indicated the Garmin GPS colors in [brackets]. I can't relate anything to inverting & non-inverting.

I retyped some of the Standard Horizon Radio and GPS information below. I can't relate anything to inverting & non-inverting.

*** NEMA DEVICE #1 ***
NMEA output (+) = COLOR [BLUE]

NMEA input (non-inverting) = COLOR
NMEA input (inverting) = COLOR

*** NEMA DEVICE #2 ***
NMEA output (+) = COLOR [GREY]

NMEA input (non-inverting) = COLOR
NMEA input (inverting) = COLOR



1. ...For Garmin units, the ground (Black) wires serve as NMEA ground and must be attached together or on the same terminal. Refer to the wiring diagram of your GPS unit for wire identification. [Diagram was included in my original post].
2. Connct the Blue (NMEA Out 1) wire from the unit to the NMEA In wire on the NMEA unit's wiring harness, and the brown (NMEA In 1) wire to the NMEA Out wire on the unit's wiring harness.
3. Repeat step 2 using the Grey and Violet wires for an additional unit.
4. Set the unit's serial port's) to use NMEA In/NMEA Out...



Blue: NMEA IN (+) From GPS navigator receiver
Green: NMEA IN (-) From GPS navigator receiver
Gray: NMEA Out (+) From GPS navigator receiver
Brown: NMEA IN (-) From GPS navigator receiver

Diagram Shows:
Radio - Blue > GPS NMEA OUT (+)
Radio - Green > GPS NMEA OUT (-)
Radio - Gray > GPS NMEA IN (+)
Radio - Brown > GPS NMEA IN (-)

Matrix Shows:
Wire Color/Description // Connection Examples
Blue: NMEA Input (+) // Connect to NMEA (+) output of GPS
Green: NMEA Input (-) // Connect to NMEA (-) output of GPS
Gray: NMEA Output (+) // Connect to NMEA (+) input of GPS
Brown: NMEA Output (-) // Connect to NMEA (-) input of GPS


Matrix shows:
Manufacturer Model // Wires // PS1000 Std. Hor.

Garmin Fixed Mounts // Blue // Blue
Garmin Fixed Mounts // Black (GRD) // Green

Garmin Portables // Brown // Blue
Garmin Portables // Black (GRD) // Green


My interpretation is that you connect:
Radio Blue to GPS Blue
Radio Green to GPS Brown
Radio Gray to GPS Grey
Radio Brown to GPS Violet
GPS to Black(Ground)


If the connections are incorrect I realize the units may not function properly but will it do any damage to either the radio or GPS?


jimh posted 05-31-2009 06:02 PM ET (US)     Profile for jimh  Send Email to jimh     
I am totally confused by your information. Let's do this one wire at a time. Tell me the color of the wire for the radio transmitter which is marked


Waccamaw Whaler posted 05-31-2009 08:58 PM ET (US)     Profile for Waccamaw Whaler  Send Email to Waccamaw Whaler     
Jim, I know you're trying to help but I posted the same information that I have in front of me. It is confusing because of the way it's presented.

None of the wires are actually tagged. I have to interpret from what I read and have copied here. It just isn't obvious.

I'm going to contact both Garmin & Standard Horizon and see what they have to say.

I'll post their feedback.


bluewaterpirate posted 05-31-2009 11:39 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
Ron ....

You're making this much to complicated. I connected a number of these units. Here's the connectivity. Image-4892322-70601210-2-Web_0_bd53425047a028aa3773709d6c950e10_1


Waccamaw Whaler posted 06-01-2009 12:39 AM ET (US)     Profile for Waccamaw Whaler  Send Email to Waccamaw Whaler     
Tom, I don't question that you are right but how did you know that you are to connect the BLUE GPS to the BLUE Radio NMEA Input (+) rather than the GREEN NMEA Input (-)?

Also, why is the BROWN GPS connected to the GRAY NMEA Output (+) rather than the BROWN NMEA Output (-)?

In othe words, what is the significance of the (+) and (-) for the Inputs and Outputs?

Doesn't it make any difference?


jimh posted 06-01-2009 09:16 AM ET (US)     Profile for jimh  Send Email to jimh     
Ron--Don't worry about the color of the wiring insulation being different. It is very ordinary that you end up connecting wires of different colors.

The markings of (+) and (-) are not polarity markings.

The (+) means the input is non-inverting.
The (-) means the input is inverting.

I think I have deciphered all the colors from your long posting. This is really simple stuff. First we find the OUTPUT from the GPS RECEIVER. You wrote:

NMEA output (+) = COLOR [BLUE]

Now we look for the INPUT to the RADIO TRANSMITTER. [Oops--we had some bad information. I don't see any value in preserving the wrong information so I have deleted it; see below for the correct information--jimh]

Also, this is only one serial data connection, from the GPS RECEIVER output to the RADIO TRANSMITTER input. Once we get this working we can figure out the connection in the other direction.

If you have a position fix on the GPS, and you make the connection, there is a good chance that everything else will be set correctly. You should see a little satellite icon appear on the RADIO control panel display.

bluewaterpirate posted 06-01-2009 12:27 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
Here's a video of my Phantom 1000 connected to a Garmin 376c. The Phantom part is in the 2nd half of the video.


Waccamaw Whaler posted 06-01-2009 12:55 PM ET (US)     Profile for Waccamaw Whaler  Send Email to Waccamaw Whaler     
I sent emails to both Garmin & Standard Horizon over the weekend. I haven't heard back from Standard Horizon yet but this is what I found out from Garmin:


BLUE to Standard Horizon BLUE
BROWN to Standard Horizon Gray
Green - not used
White - not used
Yellow - not used
Orange - not used
Violet - not used

Standard Horizon

BLUE to Garmin BLUE
GRAY to Garmin BROWN

I believe this is exactly what Tom is showing in his link. Am I right Tom?

I'm curious to see what Standard Horizn's reply is.


Waccamaw Whaler posted 06-01-2009 12:59 PM ET (US)     Profile for Waccamaw Whaler  Send Email to Waccamaw Whaler     
By the way, Garmin thinks the wires are 24 gauge and recommends soldering the connection and using adhesive shrink tubing.

I found 1/4" shrink wrap in the internet but nothing smaller. Will the 1/4" shrink that much or is there smaller dia. shrink tubing available?

jimh posted 06-01-2009 01:54 PM ET (US)     Profile for jimh  Send Email to jimh     
Heat-Shrink tubing is available in many size smaller than 0.25-inch diamater.
pglein posted 06-01-2009 03:11 PM ET (US)     Profile for pglein  Send Email to pglein     
I skipped a whole bunch of information in this thread that may have answered a lot of the questions, but I figured I'd toss in my $0.02 anyway.

In general, NMEA wiring color coding is standardized, but this does not mean that you would connect like-colored wires to each other. Typically, a certain color set represents an "out" and a different one represents an "in". If you're connecting two devices to each other, you'll be connecting the "out" from one, to the "in" from another. Thus, if the two devices use the same color coding scheme, you would, by definition, be connecting different color wires to one another.

As for making the connections, the "best" method is to use a water resistant junction box, such as the one sold by Raymarine for use in their SeaTalk systems. The box itself can be used for any small wire terminations. Fisheries Supply sells the little nylon terminal blocks that go inside them in a number of different sizes so you can accomodate multiple connections.

Otherwise, I would just twist the wires together, folding the twisted portion back over the insulation, and wrap each connection in electrical tape, and then wrapping the entire thing in more electrical tape or heat shrink.

Waccamaw Whaler posted 06-01-2009 05:24 PM ET (US)     Profile for Waccamaw Whaler  Send Email to Waccamaw Whaler     
Jim, the information I posted should be the same as the information in the link in my original post. If you open that link you will see that the pictures are scans of the actual pages from both the Garmin and Standard Horizon Owner's manuals unless, of course, I made a typo. I'm sure that information will make a lot more sense to you than it does to me. You may want to look at those pages just out of curiosity.

I appreciate the time you spent trying to help. The terminology for this exercise was completely foreign to me: NMEA in & out, + & -, inverting & non-inverting just didn't register because I had no prior reference point.

Another point of clarification, I think several people had the impresion that I was trying to match the same colors from each unit e.g., blue to blue, green to green, etc.
This was never the case but I just couldn't get things clear enough in my mind to see which colors did go together.

I'm going to have a heck of a time soldering the wires together because of the confined space under the center console and the conglomeration or other wires and equipment. I think I'll go the twist and tape route until I'm sure everything works OK. If so, I'll try to solder with the back-up being sissor type mechanical connectors and shrink tubing.

pglein - I'm not sure I could find a good spot for a junction box that I could reach and work in but that would be my preference.

It will be several days, due to weather and other commitments before I can work on the connections but I'll post my result when done.

Thanks to everyone


jimh posted 06-01-2009 05:38 PM ET (US)     Profile for jimh  Send Email to jimh     
I retrieved the owner's manual for Ron's radio from the STANDARD HORIZON website. It is available, like almost all of their products, for free download. FileCatID=86&FileName=PS1000%5FOwner%27s%5FManual.pdf& FileContentType=application%2Fpdf

The manual gives the information we need on Page 12. I cut and pasted it below:

BLUE- NMEA Input (+)
GREEN - NMEA Input (–)
GRAY- NMEA Output (+)
BROWN-NMEA Output (–)

We look at this information to see where the RADIO's NMEA INPUT is located. Voila!

NMEA Input (+) = BLUE
NMEA Input (–) = GREEN

So now, finally we have the data we need: The input for the radio to receive a NMEA signal.

We already found the output information from the GPS receiver:

NMEA output (+) = BLUE
NMEA ground = BLACK

This IS correct (at least for the radio), and the connection is as follows:



Out(+)---->In (+)
OutGnd---->In (-)

I don't find much value at all in just giving listings of what wire to hook to what wire. No one learns a thing doing that.

jimh posted 06-01-2009 09:28 PM ET (US)     Profile for jimh  Send Email to jimh     
After looking over the literature for the radio, I have to agree with Ron that the information is presented in a somewhat confusing manner. There is too much mixing of the designations of signals. The wire's functions are often referred to both in terms of their function with respect to the radio as well as the function with respect to what they will connect to. This makes it a little tricky to distinguish the input and output.

Now that we have the connection from the GPS RECEIVER OUTPUT to the RADIO TRANSMITTER INPUT, we ought to look at the connection in the other direction. This will be a connection from the RADIO RECEIVER OUTPUT to the CHART PLOTTER INPUT. In the case of the two devices in use here we find:


NMEA Out (+) = GRAY


This is a little trickier. It took me ten minutes to find it. On page 49 of the Garmin manual there is a diagram and the inputs are shown as follows


We only need to use one input, so let's use number one:


How do we connect this to the RADIO RECEIVER OUPUT? The output is a differential signal with both (+) and (-) signals. The input is a single-ended input, with only a single signal, which we assume is the (+). This means we ought to connect them as follows

BROWN ---> no connection


NMEA Out (+) = NMEA 1 In
NMEA OUT (-) = no connection

We do not want to connect the differential output signal to ground. Differential output signals should not be connected to ground, only to a corresponding differential input. Since there is none in this case, we can tape it off and leave it float.

Waccamaw Whaler posted 06-14-2009 01:37 PM ET (US)     Profile for Waccamaw Whaler  Send Email to Waccamaw Whaler     
OK, I have everything connected. Now how do I know if it's working and what am I to expect?

If I receive sound signals how will I know what they mean & how do I respond? Will they come from the radio or the GPS receiver?

Will I get any visual displays/signals on the GPS or radio?

I have the NEMA IN & OUT settings set, are there any other 'preferred' settings that should be set.


jimh posted 06-14-2009 01:48 PM ET (US)     Profile for jimh  Send Email to jimh     
Establishing serial data communication between two devices can be difficult. Fortunately, with NMEA-0183 protocols, about 99-percent of the work has already been done. All that remains is to connect the proper wires together and configure the sending device to transmit the information desired to the receiving device.

Assessing a problem in the communication link should be divided into layers. The most basic layer is the physical and electrical layer. Are the proper wires connected together? Are they electrically connected? Is the output connected ot the input? Are the non-inverting and inverting polarities consistent?

The next layer is the serial data configuration. Normally NMEA-0183 standards apply, but some device may allow for or prefer non-standard parameters. Be certain that both the sender and receiver are configured for serial data parameters that are the same, that is the same speed, number of data bits, number of parity bits, and so on.

The next layer of the link is the data layer. Is the sender sending the data that the receiver needs? A GPS receiver can typically send many NMEA-0183 data sentences. A VHF Marine Band radio may be particular about which NMEA-0183 sentence it needs to receiver in order to work. The instruction manual of the radio is the only place to find out what it needs. The instruction manual of the GPS receiver is the only place to find out what it can send.

When a proper physical and electrical connection is made, with serial data communication parameters that are compatible, and with the devices configured to send the appropriate data, the communication link should function. If all of the layers are properly configured and there is still no communication, you should begin to suspect a malfunction in one of the devices. To resolve this problem you need a third device to use as a test against the other two.

jimh posted 06-14-2009 02:06 PM ET (US)     Profile for jimh  Send Email to jimh     
"If I receive sound signals how will I know what they mean & how do I respond?

Sound signals are made via a whistle or a horn. To interpret sound signals refer to the Navigation Rules. Sound signals are not really electrical in nature.

Sound Signals In Restricted Visibility

"Will I get any visual displays [or] signals on the GPS or radio [that there has been successful data communication]?"

The GPS receiver is the sender. This is no way for it to acknowledge anything. It is just sending. In order for the GPS receiver to acknowledge that its data was sent, it would also have to be a listener and acquire data from another device. So far in this discussion we are still working on the first connection, the GPS receiver sending data to the radio transmitter. Let's hold off for a minute we get the first one working.

The VHF Marine Band radio may be able to give an indication that it has received valid data about vessel position. To learn if this happens, read the instruction manual for your radio. Some radios will display a small icon of a satellite on their display panel when the radio has been connected to a GPS receiver and is receiving valid position data. Again, this is entirely dependent on the radio. The radio instruction manual explains.

Testing the connection from the radio receiver to the chart plotter is going to be much more difficult. The radio receiver itself does not generate any data. It only receives data from a remote station, demodulates it, and makes it available on its data output wires. To test this link you will need the help of another sender, that is, a radio that will transmit some data to your receiver. When your receiver gets the data, it will send it to your chart plotter. When your chart plotter gets the data, it will do something with it, perhaps display it on its position display. But to check all of this, you'll need another radio with the proper configuration that is known to be working.

You cannot send data to your GPS receiver. The GPS receiver does not listen for data from the radio. The GPS receiver receives satellite signals, deduces its position (and other data like speed and heading), and sends this data out. But the GPS receiver does not listen for any data, at least not any that I can think of.

A chart plotter or electronic display will listen for data from other vessels and plot that data. The capabilities depend on the particular device. Again, consult your instruction manual to learn the capabilities of your particular device.

Waccamaw Whaler posted 06-14-2009 06:50 PM ET (US)     Profile for Waccamaw Whaler  Send Email to Waccamaw Whaler     
Thanks Jim, I'm fairly certain I have all the wires connected correctly and I belive I have both the radio and GPS receiver configured according to the manuals.

I believe I saw a new icon on the GPS that may represent a satellite but I don't see any mention of it in the instruction book. I don't see anything different on the radio display but I have only been playing with the setup with the boat in the driveway.

I believe you misunderstood my question regarding 'sound signals'. I was referring to bells, beeps, buzzers etc. from the Radio or GPS and what they represent. It's mentioned in the instruction booklets but lacks detail.

I think I'm at the point where I'll just have to use it and see what happens.

jimh posted 06-14-2009 10:51 PM ET (US)     Profile for jimh  Send Email to jimh     
Ron--To understand the meaning of icons or other symbols which appear on the display of your radio, get the instruction manual for the radio, and look for the illustration of the display. Generally there will be callouts which will explain what each of the many symbols and icons means when they appear. It would be unusual that there were no mention at all of an icon that was part of the display.

Many modern electronic devices employ audible feedback to indicate to the user that the device has acknowledged an input keystroke or other form of user input. These BEEPs are typically controlled by a menu setting, and can be turned on or off as the user desires.

There may also be alert signals which can be produced by a device like a digital selective calling (DSC) radio. These aural alerts are akin to the ringer on a telephone. A telephone makes an aural alert sound (RING) when an incoming call is received. In the same way a DSC radio may also make an aural alert sound when it receives a DSC call. If it did not, I don't know how the operator would be alerted to the call, unless he spent his whole day staring at the radio to watch its display. I suspect that if you read the instructions in the DSC portion of the manual you will find out about these alert tones.

Slippery Eel posted 06-18-2009 01:41 PM ET (US)     Profile for Slippery Eel  Send Email to Slippery Eel     
I have the exact same setup on my Montauk. One call to either Standard Horizon or Garmin would save you a lot of typing. Mine worked the first time. I used the smallest ancor heat shrink crimp connectors to connect the wires and slipped Ancor shrink wrap over them. No issues.
jimh posted 06-18-2009 08:35 PM ET (US)     Profile for jimh  Send Email to jimh     
One call to either Standard Horizon or Garmin would save you a lot of typing.

Believe me, it is trivial to figure out the connections between these devices, and any manufacturer worth their salt ought to show a listing of interconnections for their unit to other devices. But there is no learning in picking up the telephone and getting the answer. It is much better to spend a few minutes to calculate the solution. That's what I try to do here. I don't like to just give the answer. I like to show the process. The answer never taught anyone a thing. Understanding the process is what helps people learn.

Post New Topic  Post Reply
Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.