OK, took me 2 months to get to it.
But i just took the time to open up the cable and find the orange, blue, yellow and brown wire.
Connected it to my setup usig an optical isolation adapter so the levels are correct.
Now i have the data coming in over the USB connector, and over com 2.
Next thing to test, is to see if things will still be OK if i connect the receiver without the adapter.
But i'll have to change the cable i used for that so that's for tomorrow.
Next to that will be a test to see if i can feed GPS
data into the orange / blue wires, and whether these data will be multiplexed with AIS
data at the output.
Remind that GPS
input is @4800 baud, and output is @38400 baud.
That too will take some time to setup a GPS receiver and some cables
So i'll be back with the results of that.
By the way: earlier i spoke of RS485 , but that was incorrect.
It is RS 422, which is supposed to be the type of comms in NMEA
The data is compatible with RS 232, but the levels are different.
If only 1 RS 232 device is connected and no other devices, it will still work in most cases.
RS 485 is a 2 wire bus system, meaning any device can send as wel as receive data over the same 2 wires.