Having used the Tracker2 since its beta-test days in early 2007, I was interested in trying out the new firmware, which interfaces with a range of Garmin Sat-Nav products.
Several of the Garmin models now include their Fleet Management Interface which communicates with the Tracker2.
You'll also need a special Garmin serial converter cable to link the RS232 port on the Tracker with the GPS's USB socket, and the GPS needs to be powered from external DC in order to use this USB interface.
The Tracker2 can then do the following:
send out its own position, speed, altitude, etc;
display the position (and details) of other stations received on-air on the GPS screen;
enable the GPS to GoTo a waypoint received on-air (including a mobile);
exchange UI messages with other stations via the GPS screen;
receive control commands typed in on the GPS touch-screen.
The Tracker2 is proving to be an ideal unit for RAYNET field operations, and is now available as a product for around $95, see the Argent web-site.
Please do not attempt to use any of these functions, or let the unit distract your attention whilst driving - wait until you've stopped, or get a chauffeur!