A while ago I picked up a Holux GR-213U USB GPS receiver for pretty cheap on eBay. It's worked well in Windows, even on Windows within-a-Mac using Parallels. I thought I should give it a try using gpsd on FreeBSD, since I see nobody's reported it as working or not on their hardware page.
Stuck it into one of my FreeBSD 6.1 boxes, and saw in /var/log/messages:
ugen0: Prolific Technology Inc. USB-Serial Controller, rev 1.10/3.00, addr 2
That sounded pretty good, never messed with USB serial on FreeBSD before, so wasn't sure if the /dev/ugen0 device was what gpsd needed to talk to. Turns out it wasn't. After digging for a while, tried
and then unplugged/replugged the USB receiver - and now it shows up as
ucom0: Prolific Technology Inc. USB-Serial Controller, rev 1.10/3.00, addr 2
and a /dev/cuaU0 device showed up. I guess that makes sense in now that I see it working. The uplcom(4) module is required because the device is a Prolific chip, and that module also brings in the ucom(4) module automatically which provides the tty interface (/dev/cuaU*) gpsd needs to operate. Other USB serial devices might require a different modlue than "uplcom" - the SEE ALSO section of the ucom man page shows other possibilities.
Tried running gpsd in debug mode with
gpsd -N -n D 2 /dev/cuaU0
and was rewarded with lots of output from the receiver. Ran "cgps" and saw a human-friendly display of the GPS readings, but it kept flipping between 2D and 3D fix. Not sure what that's about yet, but at least the USB connection is working.