Cost: $75.00 (Street Price from http://www.tvnav.com/navhome.html)

This is a device that makes loading map areas into Garmin’s non-volatile memory modules easy and fast. It is easy because it doesn’t need a GPS to be running on batteries or an external source to get the maps moved from the Garmin CD to the memory module. It is fast because the time it takes to move a large-scale regional map into a 16 Meg module has dropped from four hours to under 2 minutes.

With reasonable loading times finally a reality, this simple USB interface will make the large-scale (128 meg) modules a flexible and practical tool. Had Garmin not provided this fast map loading tool, the large memory modules would have taken a life’s work to get them loaded to capacity and they would certainly not be useful for anyone moving around the country on a limited time scale needing to change the maps loaded. Here is why the old way wouldn’t be practical. When I first loaded the San Francisco Regional area into a Garmin 16 Meg module, that loading time took the better part of four hours using the computers serial port connected to my Garmin StreetPilot. Loading the map area took longer than the life of the batteries in the GPS the first time. This long map loading cycle required the construction of an external power supply to keep the GPS alive during the second map-loading attempt. If this anecdotal loading experience can be used as a rough process benchmark, to load a 128 Meg module to capacity will take 32 hours using my serial port. Not the kind of time you can spare when traveling around thinking you might want to get someplace. With this new USB device, loading this same very large 128 Meg module should be completed in less than 10 minutes.

Why is the USB faster? A USB device operates at the computer’s bus speed, whereas the serial port can be limited from at least two sources. Our first limiting source is the computer’s UART. This is a chip device that handles the serial communications of the computer and it can be severely limited on many of the older computers. At one time when the 8250 UART chips were prevalent in most computers, reliable serial port communication speeds were really limited to 9,600 baud. This chip’s design has improved and most computers sold in recent years have UART speed limits of 115,000 baud with some having even newer chips that will allow speeds of 750,000 baud.

On the GPS side, the transfer speed-limiting device is Garmin’s StreetPilot. Garmin’s black and white StreetPilot limits speeds at 37,400 baud. Moving large amounts of data this way is problematic especially with the repetitive loading reading checking writing style that Garmin employs to ensure a good load into the memory module. Now that I have this programmer for loading my maps, I’ve stopped wishing for the faster, 115,000 baud ColorMap or eMap units just to load my maps.

Initial installation of the device is like most USB devices – Simple. Plug the card into your computer’s USB port and before long the Windows 98 or Windows 2000 device wizard will appear asking for the location of the software. Point the dialog box at your CD drive location and follow the prompts. For some reason during my setup, the setup program lost the location of my CD-ROM drive so I needed to point to it twice during the process. This device will NOT work with Windows 95, Windows NT or a MAC. Once installed, the USB device can be Hot Connected. This means it can be disconnected and reconnected without turning the computer on and off to make the connection change. After the device is installed, Garmin’s software knows it is available and you can insert and remove memory modules while everything is powered up and running.

Using the Garmin Metroguide software for moving maps from the CD to the memory module is about the same with the exception that there is now a USB tab that can be selected when you select the Garmin Metroguide transfer option. This tab doesn’t appear if the USB device isn’t installed and won’t work with Metroguide versions prior to version 3.0. Garmin’s current Metroguide release is 3.05 (07/21/00) and is available from the Garmin web site http://www.garmin.com/support/download.html. If you don’t have this software version, you are living with all the old program bugs and should get the new faster bugs so that you can work with them in quicker and friendlier manner.

To load a map into a memory module, run the Metroguide software, select the maps you want to load, insert the memory module into the USB device and click on "Save To Device…" under the File menu. To change some of the maps in a large memory module, click on "Open From Device…" under the File menu, add and delete maps from the list as necessary and click on "Save To Device…" again.

Garmin units that can use this device are: StreetPilot, StreetPilot-ColorMap, eMap and GPSMAP 295. If you own any other Garmin GPS, this device won’t work with it. Desktop space for the device is about what is required for a three-button mouse (see picture below).

While this device will load the maps into the GPS modules, it won’t do anything about moving routes, waypoints or tracks to the GPS and from the GPS to computer. For this, you’ll still need the serial cable connection, an external power source for the GPS or good batteries in the GPS. This device doesn’t change anything for those of you using the Delorme mapping programs to handle your trip planning and route transfers. These limitations as some see it, are inherent in how the Garmin GPS stores information. Detailed maps are stored only on the removable memory modules. Base maps are hardwired into the GPS and route planning, tracking and waypoints are stored in a small memory space within the GPS unit itself. This small memory space is not accessible from the simple USB device because it requires memory modules to be inserted into its small opening for operation.

In summary, I’m very happy with my USB device and think it is now time to get serious about acquiring larger memory modules so that the maps we use in our GPS units will at least cover one full fuel tank’s range and then some. What I like most about how this will work over time is that with larger memory modules being available with fast loading times, it means I can pop the memory module into the USB device, load the map information into the Metroguide work area, remove areas that aren’t needed any longer, add the new areas that are required and put it all back into the memory module in about 15 minutes.

Garmin USB Device with optional Garmin Metroguide memory module

Roger…

WB1CFQ