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USB Garmin devices and NEMA data.

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Hi there. I've have a setup in my car that i'm currently quite happy with.


My car is a Toyota 4Runner. I use a Garmin 60CSx on a ProClip Quick-Release mount to the left of the car stereo. I built a custom cable to provide power and send/receive serial data from the GPS. The cable routes from the back of the GPS unit to the sleeve/molding-stuff around the steering wheel where i have installed power (RadioShack round DC plug) and serial (1/8" TRS connector) plugs. It's a pretty clean/stealthy installation overall.


Behind the dash i route the serial cable out from behind a compartment under the fan controls and attach it to my Kenwood d710a head. The power cable goes to an additional fused/switched 40amp circuit that i installed in the car that also provides power for the D710A radio mounted in the rear of the car directly from the battery. The setup is very clean and i can unplug/remove everything in about 15 seconds so the car looks stock again (i live in a city). And set it back up again in about the same amount of time.


An alarming trend that i've noticed over the past few years as GPS devices have gone more and more mainstream is the removal of the traditional serial interface from most all of the handhelds and car units. What's an APRS user to do?! :blink: (i know there are options out there.


Garmin makes standalone GPS beacons (GPS18). Some people have made standalone GPS devices specifically for the D710A even! I really like the option of sending waypoint data collected from APRS transmissions directly to the unit i'm using to navigate. The 60CSx is the last unit it looks like i'll be able to do that with.


So - 2 questions here:


1- Is it at all possible to send/receive NEMA data to these new units via (ahem) USB using some sort of bridge device? My Colorado 400t has a fairly detailed NEMA configuration, but i have to imagine that it's to send data via USB to a computer/laptop. Does anyone make a device that can be mounted in a car to interface with the new USB GPS units and provide actual 4800bps serial data to the D710a et al? (the only device i can think of or even find is an actual laptop and i don't have that kind of space behind my dash :D


2- The 60CSx is great a great unit and to make it even better it runs on straight 12v power! These USB devices can't be used in the car without providing 5v. Sure there are cigarette lighter plugs and all that, but converting something like my setup to 5v is a PITA. Not to mention that the Colorado series seems to automatically flip to "Mass storage mode" when it's connected to an external power source. Once this is fixed, or a work-around documented i'll be adding a 5v circuit to my installation i suppose.


The idea is that i'd really like to be able to use my Colorado 400t in place of my 60CSx but i don't think it's possible, nor is it going to be because of these interface problems.


So - if anyone has any input about this i'd be interested in hearing. I'm sure i'm by far not the only one who's been watching this unsettling trend!

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I have two D700 APRS setups running on outdated GPSrs. I use a Garmin II in the car and a Garmin V in my jeep. These older GPSrs are out of sight and run 24/7 on vehicle battery power. (All I have to do is hit the beacon button on the 2M rig.) The custom wiring is a pain but when it's done it's done. I like the freedom of caching with my 76CSx without the hassle of unplugging and plugging the unit every time I get in and out of the vehicle.


In the past I have used serial to USB converters to match up older and newer technologies.

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I just got a brand spankin' new Garmin Oregon 400t, and I noticed that it has the same NMEA output options. I haven't done any serious digging, since the unit is so new and not much is known about it yet.


It's also not a major concern for me right now as I have a Garmin GPS18-OEM with a DB9 serial port connected to the cable that Kenwood provided with my D700. It's just a nice small hockey puck-like GPS receiver, and it fits (and sticks via built-in magnet) nicely behind the remote display on the display mount.


While I would like to figure out the whole NMEA output bit for the Oregon (and likely the Colorado, since aside from the input methods, they seem to be very similar to each other) at some point, it's just not high on my list for the immediate future.

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So I did a brief look around for info on Garmin Spanner... Apparently it's a piece of Windows software that creates virtual COM ports (yes, it can create many of them), so that any apps that can retrieve NMEA GPS data from a serial port can do so with a USB-connected Garmin GPS.


The info I found in my quick search said that it only applied to Garmin's GPS-18 USB model, but I would imagine that any newer GPS units that have a specific Garmin Spanner interface option would work with it. I couldn't find this info on Garmin's site directly; this page came up in my Google search results:




That doesn't completely explain the presence of "Garmin Serial" and "NMEA in/out" interface options on some of the USB models... which makes me think that Garmin may be working on - or may already have, it just needs to be discovered - a serial cable that plugs into the USB port on the bottom of the unit.


Stay Tuned... ;)

Edited by virgiliomi
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Ok, just tested the Spanner software with my Oregon (in Garmin Spanner interface mode; make sure to say NO to the "Mass Storage" question)... I set up two different ports - COM2 and 3 - and connected MS MapPoint to one of them, and UI-View32 to the other. Both had no problems with receiving the data, and showed me at the same location that the GPS itself did (as would be expected).


So if you run APRS on a Windows 2000 or XP laptop with a Garmin USB GPS, then getting data from the GPS for the app shouldn't be a problem when using the Spanner software.


Now to do some more digging and see what I can find about the serial interface modes on my GPS...

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Wow, I'm on a roll today... :P


Found a page that had info on a Garmin Colorado using a Mini USB to Serial cable. They were even nice enough to provide a Garmin part number! I tried searching Garmin's site, which produced a bunch of various pages, but couldn't find reference to this cable on any of them. So I headed to one of the various GPS-specific online retailers on the web, and found this...




Obviously, the page specifies that it's for a Rino, which is Garmin's GPS + FRS radio... but apparently it works with the Colorado, and probably by extension, the Oregon.


The only downside to this cable is the fact that it doesn't provide power to the GPS. I don't know if Garmin does make a cable with serial connection that provides power... and I think I'm done searching for the day. But at least we do now know that there IS a way to take the USB connectors of some of Garmin's newer GPS receivers and get serial NMEA output from them. ;)

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Oh... and for the last point about power made by the original poster...


If you set the Oregon to use the "Garmin Spanner" interface in the settings, it will prompt you when you connect any regular USB power adapters (aside from Garmin's Oregon/Colorado-specific one) to the Oregon. Then you can politely decline to enter Mass Storage mode, and it will continue to function as normal.

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