Not compatible with Windows 10 (or 8). Discovered this after i'd upgraded the boat laptop to Windows 10. Hopefully save others the time I wasted trying to resolve .. have bit bullet and bought new one!
The BU-353-S4 version is OK with Windows 10, driver here
[Later]
The earlier version uses a Prolific USB chipset, which are pants anyway. See discussion about Windows 8 driver on GlobalSat forum. Further down the thread you will see reference to a working Windows 10 driver in post #4.
Sorry, slight thread drift and not a Windows issue, I bought a BU-353-S4 to use with OpenCpn on my Mac mini. Due to the solid construction of my Nic39's coachroof I couldn't get a decent signal at the chart table so the aerial had to go outside (it wasn't reliable at a window either). The attached cable was too short so I tried extending the usb lead with a top-grade cable but it was still flaky for me (something to do the cable degrading the signal timing?).