I have recently bought a Garmin eTrex GPS receiver to use for geocaching.
It has a "Memory-Map" USB to Serial cable, and a windows-only trial mapping program, which gave me enough clues too work out how to write a command line fist for windows and then for linux.
However I wish to also do it with my MacBook ( MacOS X 10.6.2 ) - the computer I take away on holidays for photography and now geocaching.

I have a Windows/Linux dual-booted desktop, and a Linux - Ubuntu 8.04 laptop. Both of these can read and write to the Garmin eTrex to upload or download latitude and longitude co-ordinates.
I use the terminal program gpsbabel like this :-

gpsbabel.exe -i geo -f geocaching.loc -o garmin -F com3: - for Windows

gpsbabel -i geo -f geocaching.loc -o garmin -F /dev/ttyUSB0 - for Linux

and would like to do something like this on my mac-book :-

/sw/bin/gpsbabel -i geo -f geocaching.loc -o garmin -F /devicename

BUT it says "cant open serial port 'devicename' "

I found the Linux "/dev/tyUSB0" by looking in the /dev directory and seeing a few things that looked useful.
However I can't see anything on my MacBook /dev that looks useful.

The MacBook "System Profiler > USB Tree" correctly identifies the USB/Serial cable as long as it is plugged in, but I guess there needs to be some sort of device driver with a link in /dev.

Can anybody help me please.

The Geocaching website says to use on a mac one of the GUI programs -

Garmin BaseCamp
Garmin RoadTrip
GPSContact
GPSBabel

I have all of these working, and all give the message "no Garmin PS was found".

GPSContact offers a choice of USB,Bluetooth-PDS-Sync,Bluetooth-Modem for the device to be written to, and there are tty.Bluetooth-PDS-Sync and tty.Bluetoth-Modem in the /dev directory.
The other 3 have an Input and Output icon with nothing else specified.

I had trouble with my garmin nuvi 765 when I bought it. Turned out that it didn't like the built in USB1.??? port on my computer. I put in a USB2.0 card and it recognized the nuvi just fine. Don't know if this applies to the Macbook or not.

Thanks for the suggestion, but my system profiler says "USB 2.0 hub" and identifies the USB/Serial connector in the same way as my Linux machine does.

I recently bought a new garmin gps and have been extremely pleased with it. There is a whole set of free software you can download that is extremely useful. Go download Garmin Roadtrip and check it out.

Garmin has also done a stunning job of open-sourcing their gps data files, they're all standard, fully-documented and compliant xml files. The only complaint I have is that they still make pushing information TO the gps difficult. It's very easy to read absolutely everything on the gps to the computer, but the files the computer has access to are copies of the data files on the gps, which are hidden and cannot be modified except by garmin's software. BUT, you can download them using their app, modify the xml to your heart's content, and then use their tool to reupload them to the gps. Also check out MacGPS Pro and RouteBuddy.

You will need to download the Garmin Communicator plugin for your mac. Tight browser integration (firefox OR safari !) to the point that it's almost scary how it works. But all the candy makes me really wish it were somehow integrated in with Google Maps. That would be heaven.

Hi Virtual1,

Does your garmin GPS device have a USB socket or a Serial one?

Mine has the Serial, I think I have been fobbed off with ancient stock.

I already know about the Garmin software and my original posting lists the ones which I already have on ( and working ) on my MacBook,
I have also downloaded the Garmin Communicator plug in and it finished by showing " Correctly Installed" .


The problem remains, that I can read and write from and to my Garmin GPS with both Windows and Linux, using both GUI and CLI programs.
BUT with my MacBook I get either nothing or a message that "No Garmin Device Found"

Mine has a usb port. When plugged in, it mounts up on the desktop like a flash drive, with all the data folders freely available for reading. I can even drop stuff onto it as a normal flash drive, but the gps itself would have no use for that. But I did for example, drop a copy of the complete owners manual in pdf form on it, perfect place for it.

Serial port eh? So you are stuck with NMEA support. I wrote a plugin for that many years ago. It's not a bad format. Try to find software that supports it. You won't have support for many of the newer gps features like waypoints and trackback logs unfortunately. The main use for NMEA was to allow a computer or other device to obtain current information from the device, such as location, elevation, speed, course, satelite count and strength, etc.

I used it to hook to my powerbook g3 where I had downloaded satellite imagery for the area, and with my GPS3+ feeding position information to it, my app drove a red dot around on the overhead view, james-bond style from the 60's. Rad at the time...