Hi all I have very successfully connected a BR355 serial GPS receiver direct to a Marine VHF.
I used a dc-dc converter 12v - 5v readily available from any electronics supplier.
I did not cut the PS2 cable from the BR355 but I did cut into a PS2 extension lead. The wiring diagram on the box was very useful. The unit is very quick to pick up the satellites. The system works very well in the marine enviroment