USB ports and GPS Receivers

Consumer GPS receivers first started appearing in the mid-1990s. At that time, personal computers exclusively used serial ports to interface with other devices, making it easy for hardware manufacturers to design their products to communicate through a serial port. GPS was initially popular with sailors because they could connect a GPS receiver to an autopilot or chart plotter and navigate a vessel based on GPS data. With the right cable, you can also connect your GPS receiver to a computer and download and upload data.
Serial ports are now going the way of the dinosaur, replaced by easier-touse and faster USB ports. In fact, some laptops no longer have serial ports. However, GPS manufacturers have been slow to jump on the USB bandwagon and until recently have relied on serial port connections for getting GPS receivers and computers to talk to each other.
At some point, GPS receivers with USB connectivity will eventually become widely available in the marketplace. But until that time comes (and considering the millions of GPS receivers already manufactured that can connect only through a serial port), what do you do if your computer doesn’t have a serial port?
The solution is to use a USB serial port adapter. The adapter plugs into your computer’s USB port and has a standard 9-pin connector that you can connect your serial port devices to. After you install a driver for the adapter (which comes with the product on a disk or CD), Windows recognizes the adapter as a serial port. Just connect a PC interface cable to your GPS receiver and the adapter, and you’re all set to send and receive data between the two devices.
Note this one little “gotcha” to mention regarding USB adapters: Windows might squawk that you need a driver when you plug in the adaptor, but you know you’ve already installed one. The fix: In the dialog box that’s prompting you for the driver location, tell Windows to look in the C:\Windows\Drivers directory. (This path is for Windows XP; the location varies in older versions of Windows: for example, C:\WINNT\system32\drivers in Windows 2000.) Depending on what USB devices are running at the time, Windows XP might assign the adapter to a different COM port from the last time it was used and incorrectly assume it’s a new device that needs a new driver. This abovementioned directory is where previously installed drivers are stored, saving you from having to find the original driver distribution disk. All GPS receiver manufacturers sell their own branded serial-to-USB adapters, albeit at a premium price. If you’re on a tight budget, most any third-party adapter that you buy from a computer retailer will work. These adapters tend to be cheaper than the GPS manufacturer brand-name models.