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Discussion Starter · #1 ·
Need some help from the electronics boffins please.

I bought a new cable for my Garmin 76 that has power and data connections. Problem is, it has four tinned cable ends. :eek: I don't know how to hook up the data connections.

My notebook that runs the nav systems on the boat has no serial port and only USB. How do I connect the white (serial data in) and the brown (serial data out) to a USB plug so that it will be seen by the computer?:confused:

One would think that a piece of wire that costs $35 would have some instructions :mad:
 

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██▓▓▒▒░&
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"How do I connect the white (serial data in) and the brown (serial data out) to a USB plug"
You DON'T. An RS-232 serial line needs to be connected to a hardware RS-232 serial port, aka NMEA 18x. It is not a USB port, cannot be used with one.

Serial port convertors--like pFrancs--are not really convertors, they are "emulators" and the emulation sometimes works, sometimes doesn't, depending on your OS, your software, and your computer's idiosyncracies. pFranc has a good rep--but what they are selling is still a serial port emulator, like any other on the market. If your software only recognizes serial ports, the emulator is unlikely to work even if the OS supports it.

In that case you'd need a real serial port, typically a PCMCIA card that has a real hardware serial port on it. If your software supports USB for the GPS, the pFranc is worth a try. Just make sure you can return it if it isn't reliable with your system.
 

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Grasshopper
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If I'm understanding you correctly, and if your 76 works like my GPSMAP 76Cx, then all you need is the USB cable that will connect the GPS to your laptop. This is not a powered cable, but I have a powered cable that works just as good.

I have Maptech on my laptop, and all I do is connect the GPS to the laptop (using the GPS as an antenna). With Maptech running I turn on the GPS, let the GPS find the satellites, and I'm good to go.
 

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old guy :)
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Well - it is simple, but not that simple. You had some good advice already. I have a Garmin 76 and a laptop that is running FUGAWI nav software.

I happen to have two cables, one ends in a "Y" with:

a 12 V plug connector on one side of the "Y"



Its the big thing on the right end of the cable in this picture. For now pretend the USB thing is not over on the left side of the cable in the picture.

and a RS232 Serial port connector on the other.



It is the rectangular connector on the left side of this picture.

The last picture is an adapter cable that lets you plug in the RS232 in one end and plug into a USB on your laptop with the other end.

The adapter can also look like this:



OK - that will get the Garmin "plugged int0 the PC"

From there it take a bit of tweaking. As the other post reads - it does not really connect it to a port, but "emulates" a port. I think those were his words. Again - can be done, easy "when you know how"

This is one of the advantages (some will say the only advantage) of keeping a few pet geek teenagers around to help you. With the Garmin and the RS232 and the USB emulator / adapter thing - the order you plug things in and turn them on matters.

OK - Cable #2 that I have is the cable you describe - four wires.

I have that as well and the red and black are wired into my 12 V power and the other two are wired into my little mini IT system. Over near the chart table is a computer wire with a RS232 end on it which, I plug into the USB emulator /adapter ... you know the drill here.

Easy - ya, sort of
Simple, ya sort of
Do you need patience and a bit of geeky help - well, I sure did.

And for me - once I did get it working exactly the way it should (and it will) I took a pencil and wrote on the fiberglass bulkhead right beside where the computer sits

Plug in sequence - ya da ya da
Comm port set up - - ya da ya da
Baud rate set up - ya da ya da

Cause at my age, I have a good memory, but it is short!

Cheers

I hope this helps a tiny bit
 

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If I'm understanding you correctly, and if your 76 works like my GPSMAP 76Cx, then all you need is the USB cable that will connect the GPS to your laptop. This is not a powered cable, but I have a powered cable that works just as good.

I have Maptech on my laptop, and all I do is connect the GPS to the laptop (using the GPS as an antenna). With Maptech running I turn on the GPS, let the GPS find the satellites, and I'm good to go.
I have a similar setup, 76cs with both a USB cord and serial powered cord.
I use the USB for straight into the notebook connection using Garmin Mapsource or Garmin n-route. I use the serial for connection to the Autopilot and VHF radio via nmea using the nmea out wire from the 76cs to the nmea in wire on the VHF and Autopilot. All work fine even with connecting two serial units to the one GPS. On the serial cord the black was connected to the ground for the VHF & Autopilot if I recall, not sure what I did with the red power line, I forget.
 

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Grasshopper
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How did you upload those pictures?

Well - it is simple, but not that simple. You had some good advice already. I have a Garmin 76 and a laptop that is running FUGAWI nav software.

I happen to have two cables, one ends in a "Y" with:

a 12 V plug connector on one side of the "Y"



Its the big thing on the right end of the cable in this picture. For now pretend the USB thing is not over on the left side of the cable in the picture.

and a RS232 Serial port connector on the other.



It is the rectangular connector on the left side of this picture.

The last picture is an adapter cable that lets you plug in the RS232 in one end and plug into a USB on your laptop with the other end.

The adapter can also look like this:



OK - that will get the Garmin "plugged int0 the PC"

From there it take a bit of tweaking. As the other post reads - it does not really connect it to a port, but "emulates" a port. I think those were his words. Again - can be done, easy "when you know how"

This is one of the advantages (some will say the only advantage) of keeping a few pet geek teenagers around to help you. With the Garmin and the RS232 and the USB emulator / adapter thing - the order you plug things in and turn them on matters.

OK - Cable #2 that I have is the cable you describe - four wires.

I have that as well and the red and black are wired into my 12 V power and the other two are wired into my little mini IT system. Over near the chart table is a computer wire with a RS232 end on it which, I plug into the USB emulator /adapter ... you know the drill here.

Easy - ya, sort of
Simple, ya sort of
Do you need patience and a bit of geeky help - well, I sure did.

And for me - once I did get it working exactly the way it should (and it will) I took a pencil and wrote on the fiberglass bulkhead right beside where the computer sits

Plug in sequence - ya da ya da
Comm port set up - - ya da ya da
Baud rate set up - ya da ya da

Cause at my age, I have a good memory, but it is short!

Cheers

I hope this helps a tiny bit
 

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Discussion Starter · #8 ·
I happen to have two cables, one ends in a "Y" with:

a 12 V plug connector on one side of the "Y"

Its the big thing on the right end of the cable in this picture. For now pretend the USB thing is not over on the left side of the cable in the picture

and a RS232 Serial port connector on the other.

The last picture is an adapter cable that lets you plug in the RS232 in one end and plug into a USB on your laptop with the other end.

OK - that will get the Garmin "plugged int0 the PC"
So my mental picture of this setup essentially shows a cigarette lighter plug at one end and a USB plug at the other (with some fiddling in between). How does this connect to the Garmin? My Garmin doesn't have a cigarette lighter socket on it.

OK - Cable #2 that I have is the cable you describe - four wires.

I have that as well and the red and black are wired into my 12 V power and the other two are wired into my little mini IT system. Over near the chart table is a computer wire with a RS232 end on it which, I plug into the USB emulator /adapter ... you know the drill here.
Actually I don't :( . I guess the part of this that's missing is what is the "little mini IT system" and how are "the other two" wired into it? And again, I'm still missing the part that plugs into the Garmin.

Thanks for the help but this is all a little above my understanding.
 

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Discussion Starter · #9 ·
Andre...it ain't that simple...try this:
Garmin cable: pUSB32 for 4 Pin round Garmin GPS.s

Return the cable you bought.
Thanks Cam, I already established the availability one of those connector gadgets from a supplier in NZwhich would connect with the standard Garmin cable but it doesn't solve the power problem which is my aim. The one you pointed me too also doesn't suggest that the cable provides power to the GPS. That means I still have to use batteries to power the GPS.

So connecting the Garmin to the notebook is not the problem. I need to power it through the same plug into the GPS and that's the sticking point.

Does anybody know whether any of these emulators provides power via the USB? That would be one solution. Else maybe I need to solder an RS232 plug to the data ends of my new Garmin Wonder Cable :) and connect that to the emulator with the power supply going to the 12V system separately on the red and black wires. That can't be too hard? Assuming that the emulator will work with MaxSea. :confused:

I guess I was just hoping there was some way of hooking the thing up to USB without the emulator between. Seems that's a non-starter.

Thanks everyone for the suggestions - I reckon what I'll do is solder a plug to the cable as above, try that in my old notebook that does have a serial port and if that works, start exploring the emulator option.
 

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Grasshopper
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908 Posts
I know what you're looking for now, and I thought I had one, but after doing a search online I couldn't find one...but I'm sure I have one on the boat. I bought just about every Garmin adapter I could get my hands on, to cover just about every situation I might be in. One that would do what you want it to do is Garmin Combination AC Adapter & PC 9 Pin Serial Interface Cable (010-10277-00) , except you would need the serial port on the PC. I'll look at my adapters again next time I'm at the boat, as I thought I had Combination AC Adapter & PC USB Interface Cable that was USB instead of serial.
 

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old guy :)
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So my mental picture of this setup essentially shows a cigarette lighter plug at one end and a USB plug at the other (with some fiddling in between). How does this connect to the Garmin? My Garmin doesn't have a cigarette lighter socket on it.
Actually, think of a wire with the little round Garmin connector at one end and at the other end (5 feet away) is a "Y"

  • one end of the "Y" has a cigarette lighter plug
  • one end of the "Y" has an RS232 serial plug

Does that help?
 

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██▓▓▒▒░&
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Werebeagle-
Yes, that's the most reliable thing, pure hardware with no emulator software.

Andre-
"Does anybody know whether any of these emulators provides power via the USB? " They can't provide power AND be an RS-232 standard. The RS-232 standard provides for data connections, not power. The USB standard provides two power lines and specifies 5 volts at no more than 500 milliamps be drawn from any one socket. Unless your Garmin will work from a 5 volt external power source--forget using the USB connection for power.

If I remember correctly (I have an older Garmin and wired up one of the combo cables for it, ages ago) "all in one" cords for the Garmin serial GPSes use two wires for power, typically drawn from a cigaretter lighter plug, and the remaining two wires for the RS-232 RX/TX power. Most of the time, the combo cable has to be split into two cables: One to power, the other to data. They aren't a universal solution, just a convenience of putting all the wires in one sheath for PART of the run.

These days? The world is going to a Bluetooth equipped GPS "nugget" that has internal battery power for 4-8 hours, and ditching all the cables.
 

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Telstar 28
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Omatako-

What software are you using. If you're using pretty much anything but Garmin's software, you need to connect the NMEA 0183 output to the computer somehow. IF you're using Garmin's software you can use the native USB connection.

Some of the USB-to-serial adapters will work, others won't, as it really depends on the driver and how well it was written.



To use the combined power/data cable that looks like this:



You need to connect the TX and RX lines to the proper pins (usually 2 and 3 IIRC) and the ground to pin 5 (assuming this is a DB9 serial connector) and then plug that into the USB-to-serial connector above or a serial port.

To get power, you need to jumper the ground (pin 5) to your DC ground, and then provide power to the power lead. IIRC, the power to feed a Garmin can range from 9-36 VDC for the newer NMEA 0183 units (with 5 or more pins, and 9-48VDC for the older ones that only had the four-pin NMEA plugs. BTW, the power voltage range is that of the NMEA 0183 specification, and not specific to Garmin.

BTW, the cable you really wanted to get was the one Rikhall suggested. :)
 
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