I was interested in the comments "redline" made regarding the nature of the ST60 Multi's NMEA out signal. I also observed a +12 on the NMEA+ with a small drop every 2 sec when data is being output. If I connect the NMEA+ and NMEA- directly to a serial to usb adapter no rs232 data is present (this discussion thread explains why). I ultimately want to use the ST60 Multi as a low cost seatalk to NMEA repeater for the instrument messages it does output. I want to connect to an RS232 serial to usb device (IOGear GUC232A) and read the NMEA messages with software I am developing.
I was wondering if there was a simple circuit that would convert the ST60 Multi output to an RS232 signal which could be read by the serial/usb device. Of course I can go get a Raymarine E85001 or a special opto-isolator cable (cost almost as much as the E85001) or even a nice Brookhouse NMEA Multiplexer, but for now I was looking for a low cost simple solution.
I would appreciate any good ideas that would help.