I use an AIS500 transceiver made by Raymarine. Its a "black box" with nmea output that is also a multiplexor. All my NMEA signals go to the AIS500 and it outputs 1 data stream that has all NMEA information to my laptop using a serial port. Using OpenCPN (FREE) I have a chartplotter and all instrument data is also displayed on the screen (Apparent wind, true wind, depth, speed through water, speed over the ground) I can also use the same port to output NMEA data to the tillerpilot and steer by apparent wind or steer to waypoint etc.
The AIS500 cost $530 on e-bay new. I think it has been superseded by the AIS650 now.