GPS Antenna Pigtail wiring

[robertmfranklin]

Embarrassed I could not answer this on my own.

I have an old, but new in the box. Furuno 1722C Display. I am trying to attach a Garmin GPS antenna that has a 6 wire pig tail. I have ordered a 6 socket plug which I plan to assemble to the pig tail.

I am trying to identify the male pins in the DATA 1 input, but I can not find anything on line.

This should be simple, but I have spent hours trying to figure out which wires need to match up with which pins.

Help is gratefully appreciated.

[Paul Elliott]

It looks like the socket on the Furuno 1722C has seven pins, not six: Furuno manual (see page 2-5) http://www.furunousa.com/ProductDocu...n%20Manual.pdf

I suppose you would want to connect to the Data1, Data2, or Data3 pins, and ground. This is a single-ended NMEA, not the standard balanced connection, but it usually works.

The Garmin GPS you (probably) have uses the connections shown on page 4 of this manual: http://static.garmin.com/pumac/GPS19x_HVS_INST_ML.pdf

The signals you will use are TX-A (Gray) and ground (Black). You will obviously need to also connect power and ground.

You will need to set the Furuno to match the GPS port speed, usually 4800 bits/second. The furuno manual describes how to do this. If you don't get data, try using the GPS TX-B instead of TX-A (these have opposite polarities). Whichever TX you use, leave the other one disconnected.

[robertmfranklin]

Paul,

That was wonderful. I will print your reply.

Yes the Furuno has a 7 pin male seeking a 7 pin female from the GPS antenna. I have the female 7 pin socket on its way to me. I planned to install the GPS wires into it.

My problem is knowing how to match the 7 wires that come from the Garmin pigtail into the female socket so that each connects to the correct mail pin on the Furuno 1722C. I am fairly skilled at making up the plug, and I have the Garmin wire schematic showing which color is used for which purpose from the antenna. For example, red is 12v. etc.

I just do not know what each male pin coming out of the display is for.

Maybe I should have purchased a female socket pig tail to just connect up to the Garmin pig tail. But even then I could not be sure. The only way to be sure of the correct connection is to do it my self. But first I have to know what each pin in the Data 1 is for.

Sorry, if I have made this more complicated than it needs to be, but I certainly don't want to wire up anything incorrectly.

[Paul Elliott]

Robert, I suggest that you first try the connections by using clip-leads, or just twisting wires together. You will have to make sure that the signal polarity is correct, and also make sure that you can set the port bit rate to match. The Furuno has several NMEA inputs, and I don't know how flexible they are -- some may have different options than others. It may take a few trials and errors before you find the magic combination. Don't bother soldering or crimping your connections until you've got it working -- I've been there, done that! A good thing about NMEA 0183 is that the signals are slow, so neatness doesn't matter that much.

Also, it looks like the default Garmin GPS bit rate is 38400 bits/second. (Again, assuming you have the GPS19x). If the Furuno can support this, there's no reason not to use it. If necessary, Garmin describes how you can reduce the bit rate to 4800 in the installation manual.

[robertmfranklin]

Paul, and others.

Since yesterday, I have done a lot of reading and testing. I just need to get over the last small hump and I think I'll be set.

I have the Garmin GPS 7N antenna. It has a pig tail with 8 very small wires.
Red, Black, Yellow, Blue, White, Green, Violet, Gray.

For what I am trying to achieve, 4 are relevant. Red, Black, Blue, White. Yellow is some kind of switch for the power. Green and Violet, I think replicate the functions of the White and Blue. Gray is described as PPS, which I think is plulse per second. I am not at all clear as to what that is about.

All I want to do is connect the Antenna propery to the Data 1 plug on the back of my Furuno 1722C 7 inch display.

Black and Red are easy. Red takes 12 V and Black is negative or ground.

White white is data out Antenna and Blue is data into the Antenna from the 1722C.

The problem is I do not know which pin on the 1722 provides the data to connect up with the blue wire and which pin accepts the data coming from the Antenna.

The plug at the 1722C is 7 male pins in a circle with the key at 12 O'clock. Facing the plug, the pins are numbered 1,2,3, 4 (at 6 O'clock) then 5, 6, 7.

By testing I have determined that pin 5 delivers 12 volts, so the red from the antenna must connect there, 6 and 7 each complete the power circuit and give my multimeter the 12 volt reading.

Pin #2, give 5 volts when grounded to 6 or 7.

My assumption (always a risk) is that pin 1 accepts data from the white wire. In other words white is data out from the antenna and is received at pin 1 on the 1722C. I am guessing that the 5 volt reading at pin2 is because that pin is producing data at the 5 volt level or transmission. This is just a guess and might not be a good one.

Because the electrical schematic at the back of the Furuno Radar Intallation Manual seems to suggest that Pin1 and Pin2 labeled TD2-A and TD2-B respectively are both data transmission from the 1722C out to somewhere.

This schematic confirms what my multimeter test indicated, namely, that Pin 5 is 12V and that pins 6 & 7 are both ground.

Here is another guess: The white wire from the Antenna is data being transmitted from the Antenna to the 1722C and one of the other wires either the green or the violet is identical. Some of my reading suggests that two NMEA 0183 devices can be run off the GPS Antenna and that would explain how it is done.

OK. I've probably rambles on excessively.

Basically the question is where do blue and white go?

It is difficult to imagine doing this by trial and error. First I am not on the boat, have little open sky available and working with the pins so close in side the plug is a real challenge. Also. What should I expect to see if I get the blue and white from the Antenna pigtail to the correct pins of the 1722C?

Bob Franklin

From reading the manual and elsewhere I have determined the following:

Red is for 12 Volt in. Black is ground.

[Paul Elliott]

Originally Posted by robertmfranklin

Paul, and others.

Since yesterday, I have done a lot of reading and testing. I just need to get over the last small hump and I think I'll be set.

I have the Garmin GPS 7N antenna. It has a pig tail with 8 very small wires.
Red, Black, Yellow, Blue, White, Green, Violet, Gray.

For what I am trying to achieve, 4 are relevant. Red, Black, Blue, White. Yellow is some kind of switch for the power. Green and Violet, I think replicate the functions of the White and Blue. Gray is described as PPS, which I think is plulse per second. I am not at all clear as to what that is about.

All I want to do is connect the Antenna propery to the Data 1 plug on the back of my Furuno 1722C 7 inch display.

Black and Red are easy. Red takes 12 V and Black is negative or ground.

White white is data out Antenna and Blue is data into the Antenna from the 1722C.

The problem is I do not know which pin on the 1722 provides the data to connect up with the blue wire and which pin accepts the data coming from the Antenna.

The plug at the 1722C is 7 male pins in a circle with the key at 12 O'clock. Facing the plug, the pins are numbered 1,2,3, 4 (at 6 O'clock) then 5, 6, 7.

By testing I have determined that pin 5 delivers 12 volts, so the red from the antenna must connect there, 6 and 7 each complete the power circuit and give my multimeter the 12 volt reading.

Pin #2, give 5 volts when grounded to 6 or 7.

My assumption (always a risk) is that pin 1 accepts data from the white wire. In other words white is data out from the antenna and is received at pin 1 on the 1722C. I am guessing that the 5 volt reading at pin2 is because that pin is producing data at the 5 volt level or transmission. This is just a guess and might not be a good one.

Because the electrical schematic at the back of the Furuno Radar Intallation Manual seems to suggest that Pin1 and Pin2 labeled TD2-A and TD2-B respectively are both data transmission from the 1722C out to somewhere.

This schematic confirms what my multimeter test indicated, namely, that Pin 5 is 12V and that pins 6 & 7 are both ground.

Here is another guess: The white wire from the Antenna is data being transmitted from the Antenna to the 1722C and one of the other wires either the green or the violet is identical. Some of my reading suggests that two NMEA 0183 devices can be run off the GPS Antenna and that would explain how it is done.

OK. I've probably rambles on excessively.

Basically the question is where do blue and white go?

It is difficult to imagine doing this by trial and error. First I am not on the boat, have little open sky available and working with the pins so close in side the plug is a real challenge. Also. What should I expect to see if I get the blue and white from the Antenna pigtail to the correct pins of the 1722C?

Bob Franklin

From reading the manual and elsewhere I have determined the following:

Red is for 12 Volt in. Black is ground.

The PPS signal is indeed Pulse Per Second. This is used in some timing applications and you can safely ignore it.

You don't need to connect anything to the data input of the GPS. This can be used to change the GPS configuration, and the output sentences that the GPS delivers. I think that your GPS will default to a useful state without any changes.

I suppose that the +12V output from the Furuno will power the GPS, but it might not be able to supply enough power. I would at least check this with a voltmeter once you hook it up.

Unfortunately, I can't find any specs on a Garmin "GPS 7N', and the wire colors you have don't match those of the GPS 19x, so your guess is as good as mine. You will need to connect Ground, 12V, and Data Out from the GPS. You should be able to ignore any other wires.

Do look at the pinout shown in the Furuno document I linked to above. This shows that pin 6 of the panel connector is for an external buzzer. This is probably at ground when the buzzer is not activated. The pins you want are:
2 (Receive Data) -- connect this to one of the GPS Data Out wires
5 (+12V) -- this may not provide sufficient current???
7 (Ground) -- connect this to GPS Ground

[robertmfranklin]

Paul,

One last check, please.

Based on the Furuno link, wouldn't it be pin 3 on the 1722 that takes the data in from the GPS Antenna, not pin 2. Pin 2 is putting out 5 volts so I am concerned about attaching data wires whether they are in or out to that pin.

In the schematic from the Furuno link, I assume the plug on the right with the list of 7 pins represents the 7 pins at the back of the 1722. In this schematic. pin3 is RD-A, which I interpret as "Receive Data". Pin 2 also says RD, but my multimeter test indicates it is live with 5 volts of power. Why would there be 3 data received pins and only one of the three producing power. Somehow it just doesn't make sense.

I should probably start by wiring the white wire, which is data out of the GPS antenna to pin3 on the 1722. If that works, I'm done. Pin2 with voltage worries me. It definitely has 5 volts.

[Paul Elliott]

Originally Posted by robertmfranklin

Paul,

One last check, please.

Based on the Furuno link, wouldn't it be pin 3 on the 1722 that takes the data in from the GPS Antenna, not pin 2. Pin 2 is putting out 5 volts so I am concerned about attaching data wires whether they are in or out to that pin.

In the schematic from the Furuno link, I assume the plug on the right with the list of 7 pins represents the 7 pins at the back of the 1722. In this schematic. pin3 is RD-A, which I interpret as "Receive Data". Pin 2 also says RD, but my multimeter test indicates it is live with 5 volts of power. Why would there be 3 data received pins and only one of the three producing power. Somehow it just doesn't make sense.

I should probably start by wiring the white wire, which is data out of the GPS antenna to pin3 on the 1722. If that works, I'm done. Pin2 with voltage worries me. It definitely has 5 volts.

Based on the Furuno installation document that shows a connection to a computer's serial port, I'm pretty sure that Furuno pins 2, 3, and 4 are inputs, and pin 1 is data output. You can use either pin 2, 3, or 4 (and then configure the appropriate Furuno NMEA port for baudrate).

I don't know about the 5V you measure, but this may be a very weak bias voltage, perhaps to keep a disconnected input from generating noise? I agree that caution is called for, but it's unlikely that a wrong connection is going to kill anything since the inputs and outputs are generally well protected from this kind of fault.

But yes, connecting GPS "data out" to Furuno pin 3 should work. Pin 3 is the RD_A input.

[robertmfranklin]

I think I am all set. I'll try to get to it tonight and report back. I have an old lap top with a DB 9 (the newer ones don't have that). So I am going to try that hook up, too.

I'll report back on my success or otherwise.

Your help talking me through has been invaluable.

Bob Franklin

[Paul Elliott]

You are certainly welcome, Bob, and I hope my advice proves to be useful. I hope it doesn't all goes up in smoke! (Of course that's quite unlikely.) Please do let us know how it works.

[robertmfranklin]

Paul,
My last posting was January 19, 2017.

Since then I have tried to connect the Garmin GPS antenna to my Furuno 1722C display without success.

The Furuno wiring diagram for Data Port 1 is:
Pin 1 TD-A
Pin 2 TD-B
Pin 3 RD-A
Pin 4 RD-B
Pin 5 +12V
Pin 6 GND
Pin 7 Shield

The GPS wiring in the owner's manual is:
red 12 V (6 -40 VDC)
Black - Ground
Yellow: Remote ON/OFF
Blue: Port 1 Data in
White: Port 1 Data out
Green: Port 2 Data in n/c
Violet: Port 2 Data out n/c
Gray: PPS n/c
Bare Wire: Drain n/c

I have all the wires attached to connectors ready to install in a terminal strip. So I can change connections easily.

I am so frustrated. All I get is a message, "No Data" The lat and lon are blank.

Usually I am pretty good at this sort of thing, but this time I am stumped. It looks like only 4 wires from the antenna are involved. I have connected the black and red to the appropriate pins on the Furuno. This leaves Blue and White from the antenna to go to the Furuno. That should be easy, but I would like you to walk me through it, once again.

Also, I cannot find on the Furuno where to adjust the baud rate.

Bob Franklin

[Paul Elliott]

Bob, I suspect that you have a baud rate problem. The Furuno box is probably looking for a 4800 bit/sec input, and the GPS may be putting out data at 38,400 bps. The rates have to match or you will get nothing at all.

Section 3-6 of the Furuno manual (http://www.furunousa.com/ProductDocu...n%20Manual.pdf) shows how to set the serial port.

Or, the GPS may be broken. Or, you still haven't stumbled across the correct wiring configuration.

At this point I suggest you debug this with a computer with a serial port (a USB-to-RS232 adaptor will work well enough, even though your nav gear is using balanced NMEA0183).

You can use a terminal program to see if the GPS is working and putting out data, and at what baud rate. You can also use a nav program such as OpenCPN or NavMonPc (which I wrote) to connect to the GPS. This way you can troubleshoot each end of the connection independently. Let us know if you need help with the PC, program, or serial connections.

If you can find someone who has an oscilloscope they might be able to help you troubleshoot this.

[robertmfranklin]

Paul,
I read the tech specs on the Garmin 17N. It says that the baud rate is 4800. My Furuno display was set at 4800. The 17N is "new" in that it has never been in use until now, so I kinda doubt it is broken. It was "bundled" with the Furuno 1722 when sold to a friend of mine by West Marine. My guess is even though a different brand it was intended to work out of the box.

I think my problem lies in the wiring and would like your suggestion from what I sent earlier.

Question. If the white wire coming from the antenna is "data out" do I need to be concerned about any other data wires if I just want to get a position. In other words, should I be able to acquire a lat lon if I just have the white, red and black, attached?

[smac999]

You probably need to ground the yellow wire to turn the gps on. (Pretty sure Garmin grounds it)

As posted above use a computer to check output if still not working.