[LW] [LW11] ST60+ graphic NMEA out

[tmendast]

Hello,

have been trying to get supported NMEA sentences out of my ST60+ graphic repeater.
Done so far:
-NMEA out is set ON via usercal ("alarm drive unavailable" was shown)
-bought USB to RS422/485 converter from "US connectors"
-installation of the USB-converter on my computer is verified and ok
-connected the lead NMEA out +/- to Rx+/Rx- of the USB-converter

Result: no data, regardless of the connection of the GND-pin of the converter.

Did some measuring on the ST60+ graphic and observed that the NMEA out+ is stable 10.8V. My conclusion was that as the NMEA out is also used for driving auxiliary alarms there is some kind of on/off switch on the NMEA-. So I connected an artificial load of 1kOhm between the NMEA+ and NMEA- and was able to detect valid NMEA waveforms with my oscilloscope between NMEA- and the grey SeaTalk pin of the graphic display. Did not measure the voltage levels as I thought it would be better to ask you first what is my best option (buying the E85001 is not).

So how can I get the NMEA sentences out of the ST60+ graphic ?
Of the supported sentences I need the MWV (the wind) the most.

I am able to measure, solder and build simple circuits out of discrete components. It would be very helpful to know how the output stage of the ST60+ graphic is designed.
The ST60+ graphic was installed on my boat 2006 as have my all other Ray instruments.

With best regards,
Teijo Tmendast