This may be unrelated, but
I have a
Globalstar BU-355 PS-2 with a second PS-2 to USB cable, and was just using it this morning on the PC with 3.3.814 through Com3 at 9600 and 57000 baud using the Prolific driver. At first I was having some trouble getting it to run properly at 4800 baud. No NMEA in the GPSinfo Utility. I then tried SirfDemo 387 demo utility and was able to see the NMEA. I reset the BU-355 to 4800 baud, closed SirfDemo, and tried GPSinfo utility. No dice.
Then removed USB
plug safely. Waited a little and reinserted. Now the
puck sees NMEA at 4800 baud. I must say that more often I run it at 9600 baud when on the PC, and then it just seems to
work coming up on Com3, and Opencpn finds it right away.
I have to have 4800 baud when I am using it connected to my Standard Horizon
DSC VHF with a second PS-2 cable directly wired to 5v supply and
VHF nmea in and out and ground, because the VHF requires 4800 baud.