I have interfaced the BR-355 to my marine VHF/DSC radio using a slightly different approach than a previous poster. To make it easy to install and test the components separately, I constructed a small (1"x2"x3") project box that contained a PS/2 jack for the BR-355, a stereo audio jack for the VHF, a 5 VDC regulated power supply with USB jack, and a hard-wired, fused lead to the 12 VDC boat supply and ground. The VHF that I used had 3 bare wires: GPS in, GPS out, and signal ground. All permanent connections were made in the box. That way there is no need to cut the end off the BR-355 cable, and the VHF is easily removable for testing and repair.
I can report that the BR355 and Standard Horizon GX1150 work together flawlessly.