Connecting a Garmin USB GPS

Electronics Hookup and Configuration

Introduction

Over the last decade, Garmin has released hundreds of different GPS models. However, with few exceptions, they all use one of three different communication protocols. Usually, it is a matter of choosing the correct setting in Terrain Navigator Pro to share markers, routes, tracks (and in many cases, maps and photos) with your Garmin GPS.

Serial Connections

The oldest style of Garmin GPSs use a serial cable to connect with the computer. This is no longer common, due to the prevalence of USB-style connections. If you have a Garmin GPS with a serial connection (which looks like a D shaped plug with 9 pin holes) please refer to these technical documents for tips and tricks:
Configuring Terrain Navigator (or Pro) to the GPS - Basic Instructions
I don't know what COM Port my GPS is connected to. What should I do?
Connecting a Serial GPS to a USB Port
Determining the COM Port of a USB to Serial Adapter

Note that some Garmin GPSs used both a serial and USB connection.

USB Connection: Garmin Protocol

Prior to 2008, virtually all Garmin GPSs using a USB connection employed this style of interface. These include the GPSMap 60, the eTrex Venture, and many other popular units.

To connect this style of GPS to Terrain Navigator Pro, either use the GPS Setup Wizard (found in the GPS menu) or select the Setup option in the GPS menu, set the Manufacturer to Garmin, and the Unit to the best match for your GPS (as long as the Unit includes USB in the description.) If your unit is not shown, usually the 'GPSMap 276CSx USB' is the best match.

Once you have set this up, open the GPS menu and choose Receive from GPS, Receive Waypoints (or a similar function.) This will ensure that the connection is working properly.

When I attempt to send or receive waypoints (or connect to the GPS) I receive an error: "USB open failed". What does that mean and how do I fix it?
An USB open failed error indicates that the driver used by the Garmin GPS to connect to the Windows operating system is either damaged or missing. You can correct this by downloading and installing the latest USB Drivers software for use with all Garmin GPSs. This ensures that all the drivers are installed and that the connection is working properly. You can find the Garmin USB Drivers software at:
http://www8.garmin.com/support/download_details.jsp?id=591

Once he Garmin USB Drivers software is installed, Terrain Navigator Pro will be able to detect the GPS properly (and open the connection to the USB port.)

USB Connection: Memory Card Protocol

Most Garmin GPSs manufactured after 2008 use a new "memory card" protocol. This protocol is very similar to a digital camera or USB "memory card" in that the GPS appears as an external memory disc to the Windows operating system. This has its advantages as it means that no additional drivers are required for sharing markers, routes, tracks, and (in most cases) maps and aerial photos. However, a separate driver/configuration is required for using the GPS to track your position in real time on the Terrain Navigator Pro display. This driver is available at:  http://www8.garmin.com/support/download_details.jsp?id=591

Garmin GPSs that use the Memory Card Protocol include the Colorado, Oregon, Montana, Dakota, GPSMap 62/64, GPSMap 78, and eTrex 20/30.

To connect this style of GPS to Terrain Navigator Pro, either use the GPS Setup Wizard (found in the GPS menu) or select the Setup option in the GPS menu, set the Manufacturer to Garmin, and the Unit to the best match for your GPS. If your unit is not shown, usually the 'GPSMap 62s USB' is the best match.

Once you have set this up, open the GPS menu and choose Receive from GPS, Receive Waypoints (or a similar function.) This will ensure that the connection is working properly.

Related Troubleshooting Tips:
Why do I get a GPS Error about 'two modes of operation' and how do I correct it?
Sending Maps (and Photos) to Garmin GPS Units

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