NMEA wiring issue with Garmin 541S and Uniden UM380

[KRH1326]

Hello All,

Racing to get my prep work done and of course, Garmin and Uniden's Customer Service/ Tech are closed for the whole weekend....

I am utterly confused with the NMEA wiring, as Uniden shows two different drawings, and Garmin's is different, as well.

Can someone help me sort this out, so I can wire them up, together, tomorrow?


Uniden Specs

See attached pic


Connecting to a GPS receiver
If you connect the radio to a GPS receiver, the radio can automatically transmit your current position during an automated distress call or during a normal DSC call.
Your radio supports a standard NMEA0183 input from a GPS receiver. Follow the steps
below to connect your radio to your GPS receiver:
1. Connect the BARE wire of the included accessory cable to the GROUND WIRE on your GPS receiver.
2. Connect the YELLOW wire of the included accessory cable to the GPS DATA OUTPUT WIRE on your GPS receiver. Below is a table of common GPS receivers and the proper connections:

See attached pic


Connecting to a Chartplotter
Your radio provides a standard NMEA0183 GPS output that you can connect to a
chartplotter. When it receives another boat?s position data in a DSC call, the radio sends the position data to the chartplotter so you can see the location:
1. Connect the BROWN wire of the accessory cable to the NEGATIVE (-) wire of your
chartplotter?s NMEA data INPUT.
2. Connect the WHITE wire of the accessory cable to the POSITIVE (+) wire of your
chartplotter?s NMEA data INPUT
3. Be certain all wire connections are secure and that all open wires are adequately
covered.

Garmin Specs


See two attached pics.





Sorry for the pics but I have this all in a word document, I copied and pasted, but the photo's done paste...

Thanks for any help... Kenny

 

[NYBo]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

Can't read the labels in the second pic.

Basically, you connect the NMEA "in" on one device to the NMEA "out" on the other, observing polarity (+ and -).

 

[KRH1326]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

I really did think along those lines, but the three descriptions just dont match.
Is there a way that I can post the whole word doc, with legible pics, or send this to a person that may be able to make sense of this?

 

[dingbat]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

As noted above, Output from GPS goes to input of Radio

Blue on the Garmin goes to Green or yellow on the radio. Blk goes to blk, might have to connect the bare wired from the radio to blk as well.

 

[KRH1326]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

OK that part I get... But if you look at the chartplotter function, it is asking for the Brown and White to be connected to positive and negative NMEA's, and the garmin drawing doesn't look like either of the Uniden ones.

 

[NYBo]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

There is no standard color scheme for this wiring. Rely on the description of the function of each wire.

 

[dingbat]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

OK that part I get... But if you look at the chartplotter function, it is asking for the Brown and White to be connected to positive and negative NMEA's, and the garmin drawing doesn't look like either of the Uniden ones.

I repeat....blue (out) on garmin goes to grn or yellow (input) on radio. Blk to blk

 

[KRH1326]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

Thank you guys

Dingbat, I am sorry if I seem confused... Maybe the functionality is what I dont understand.

I agree that the Garmin Blue goes to Uniden Yellow. I understand that this allows the GPS to tell the Uniden my position.

I agree the black to black takes care of the ground.

Here is what I dont understand: This model Uniden is supposed to be able to communicate, back to the GPS, and tell it the fix of an incoming DSC. So that would need an output to the GPS.

Here it is again:

Connecting to a Chartplotter
Your radio provides a standard NMEA0183 GPS output that you can connect to a
chartplotter. When it receives another boat’s position data in a DSC call, the radio sends the position data to the chartplotter so you can see the location:
1. Connect the BROWN wire of the accessory cable to the NEGATIVE (-) wire of your
chartplotter’s NMEA data INPUT.
2. Connect the WHITE wire of the accessory cable to the POSITIVE (+) wire of your
chartplotter’s NMEA data INPUT
3. Be certain all wire connections are secure and that all open wires are adequately
covered.

I understand the Uniden white connects to Garmin brown (Line 2, above)
What I am asking for help with is how to do Line 1. I can identify the Uniden brown, but what would be the "NEGATIVE (-) wire of your chartplotter’s NMEA data INPUT" ? The Garmin diagram does not show a wire by that name, and I am not that versed to just get it by technical description.

I really do appreciate the help.

 

[dingbat]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

Forget all the text. It's doing nothing but confusing you. It simple.... In goes to out....Transmit to receive... Rx to tx

Garmin Brn or violet (input) to radio Brn or white (output)

 

[KRH1326]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

Ahhh, Thank You

 

[jhebert]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

When manufacturers implemented NMEA-0183 they often give the signals confusing names. There was no color code in the standard. One has been proposed, but I don't believe it has been adopted by manufacturers.

A good guide for interfacing of NMEA-0183 signals is found at

continuousWave: Whaler: Reference: NMEA-0183 Interconnection Guide

Adding to the confusion is the use of both single-ended and differential signals.

 

[KRH1326]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

Thank you everybody for all of the help and information.

As it turns out, I believe, is that Uniden did not provide an accurate wiring diagram. I have found that others have had this same issue.
The diagram in my manual and the diagram available online at Uniden does not match the harness that is factory installed on my unit.

Please see the developement of this post:
Need Help with wiring garmin 740s - The Hull Truth - Boating and Fishing Forum

When I ask my question, please do not spit out a hasty "color to color" that I sort of understand already, I am asking for a little more....
If this other post is correct, and the Garmin Tech was accurate ( I have a huge problem understanding the orange wire ) then I think that my wiring needs to be as follows:

UNIDEN UM380

POWER WIRES
Red: + bus
Black: - bus

Harness
Red: Ext. Speaker + I don't need
Black: Ext. Speaker - I don't need
Green: GPS Data In (+) To Garmin BLUE NMEA 1083 port 1 Tx(out)
Bare: Ground Does this shield wire still get wired to Garmin's Black ground to - bus ???
Yellow: NMEA Out (+) Wired to Garmin BROWN Garmin Port 1 Rx(in)
Orange: NMEA Out (-) ???? Wired to Garmin's Black ground to - bus ????
Brown: I do not think I need this.
Blue: I do not think I need this.

My questions are: Does this look right? AND What does this orange wire have to do with it?

 

[NYBo]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

What are the labels for the Garmin wires? What you listed above looks to be correct.

Once you have the wiring figured out, you have to make sure the two units are speaking the same specific language: baud, # of data bits, # of stop bits, just like setting up an old-school modem.

 

[KRH1326]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

Does the Uniden orange wire to ground look right to you, as per Garmin tech?

The Garmin wires are as the diagram states:

RED POWER
BLACK Ground ( power and NMEA 0183)
Blue NMEA 0183 port 1 Tx (out)
Brown NMEA 0183 port 1 Rx (in)
Grey NMEA 0183 port 2 Tx (out)
Violet NMEA 0183 port 2 RX (in)
Green CANet L
White CANet H
Orange Accessory on
Yellow Alarm low

 

[dingbat]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

The radio has two (2) NEMA channels so you can connect a second NEMA device.
Bare to garmin blk

 

[KRH1326]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

OK radio has 2 NMEA channels, and bare to garmin black.

Does the Uniden orange look right to you? connected to ground?
And does the wiring that I think I figured out look right to you?
all on post 12?

 

[DerekF]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

Green: GPS Data In (+) To Garmin BLUE NMEA 1083 port 1 Tx(out) Yes
Bare: Ground Does this shield wire still get wired to Garmin's Black ground to - bus ??? Yes connect shield to the garmin ground and the -ve bus
Yellow: NMEA Out (+) Wired to Garmin BROWN Garmin Port 1 Rx(in) Yes
Orange: NMEA Out (-) ???? Wired to Garmin's Black ground to - bus ???? No, this should be left unconnected.
GPS Data In (-) wire needs to be connected to Garmin ground (and -ve bus).


The Uniden has a differential signal which means two receive wires and two transmit wires (+ and -).
The Garmin has a single ended port with one receive wire Rx and one transmit wire Tx only. But it has two single ended ports so you can connect two different pieces of NMEA equipment to it.

The general rule is to never connect a transmit wire (either +, -, A or B) to ground. The NMEA Out (-) will be a mirror image of the NMEA Out (+) signal. If you attach this to ground, whenever the Uniden transmits a signal you will be shorting the signal to ground. This will cause excess current to flow and might damage the circuit. Therefore it gets left unconnected.

The GPS Data In (-) on the other hand needs to be connected to ground so that there is a voltage difference between the GPS Data In (+) and the GPS Data In (-) for the Uniden to read. It is safe to connect receive wires to ground because they don't transmit any power.

This document gives a pretty good explanation of NMEA signals and Page 9 and 10 show how to connect single ended and differential NMEA devices together.
http://www.actisense.com/products/n...ownload=271:nbf-3-nmea-0183-information-sheet

 

[jhebert]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

...When I ask my question, please do not spit out a hasty "color to color" that I sort of understand already, I am asking for a little more...

Yes, I agree. That's why I never respond to inquiries like these with only color-to-color responses. If you spend a moment reading my guide, I think you can figure this out yourself with no problem.

...The general rule is to never connect a transmit wire (either +, -, A or B) to ground. The NMEA Out (-) will be a mirror image of the NMEA Out (+) signal. If you attach this to ground, whenever the Uniden transmits a signal you will be shorting the signal to ground. This will cause excess current to flow and might damage the circuit. Therefore it gets left unconnected.

This is good advice, but seldom given. Too often responses instruct people to connect the TALKER B signal to ground, a bad idea.

The interconnections are much easier to make if you first translate all the manufacturer names to the proper NMEA names of TALKER A/B and LISTENER A/B.

http://continuouswave.com/whaler/reference/guideNMEA0183.html

 

[jhebert]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

This document gives a pretty good explanation of NMEA signals and Page 9 and 10 show how to connect single ended and differential NMEA devices together.

http://www.actisense.com/products/n...ownload=271:nbf-3-nmea-0183-information-sheet

Yes, that is a good but very technical presentation. It is probably too technical for most boaters.

The NMEA-0183 interface is really unworkable for the average boater. The US Coast Guard has asked NMEA to revise the standard to make it more practical.

 

[KRH1326]

Re: NMEA wiring issue with Garmin 541S and Uniden UM380

I thank you guys very much.
Ok, then, I guess I can not finish wiring this yet as I don't have an accurate color key to identify uniden's GPS Data In (-).
I agree that this is not rocket science, but if you have never dealt with it, and are trying to learn some of it, you really need good and accurate advice... give a man a fish...


UPDATE:

I am posting this here, to help the next guy, who faces this issue.
Uniden changed their wiring harnesses on certain models, AND HAS NOT UPDATED EITHER PRINTED OR ONLINE MANUALS AS OF YET.

This applies IF THERE IS AN ABSENCE OF A WHITE WIRE IN THE HARNESS.

As per both Uniden Tech Support AND Garmin Tech Support:

Uniden GREEN (NMEA + In Rx) is wired to Garmin BLUE (NMEA port 1 Tx Out)
Uniden YELLOW (NMEA + Out Tx) is wired to Garmin BROWN (NMEA port 1 Rx In)
Uniden ORANGE (NMEA - In Rx) is wired to Garmin BLACK grounding wire.
Uniden BARE/SHIELD is wired to Garmin BLACK grounding wire.

Anyway, this might be a good post to hang on to, as it applies to almost all of the Garmin fixed mount GPS units.