macos ais data from usb serial cable from gps

[sailalibi]

My usb serial cable from digital yacht worked perfectly from my garmin 545 to my windows 10 pc. Now it wont work to my mac os catalina. Ais data comes from a standard horizon gx2400 to the 545 and displays ais data just fine but the macos doesnt see the usb input data. Any help is appreciated!

[KompetentKrew]

I would reboot the computer or start it up without the dongle attached.

Open Terminal.app (in Applications > Utilities), type ls /dev > unattached.txt and hit enter.

Now plug in the dongle, wait a minute and ls /dev > attached.txt

What does diff attached.txt unattached.txt say?

[sailalibi]

The diff command says they match. IT seems that the mac thinks the usb attached is a bluetooth serial import port and assigns it RFCOMM CHANNEL 3. I can't see how to tell the open cpn connection that number. The usb plug lights up an flashes a red and green led together for about 5 times then goes dark

[KompetentKrew]

That's not what I expected - I'd have expected a device node to be created when the USB dongle was plugged in. I'm not familiar with this model of adaptor but I might expect it to be something like /dev/tty-something or /dev/usb-something. However, I can see that my system currently has /dev nodes for at least one bluetooth device that isn't plugged in, so the test I asked you to do may not be conclusive. You might just have to ls /dev and see if you can spot any likely candidates.

Click on the black Apple in the top left corner of the screen and "About this Mac" and then, in the window that pops up, "System Report". See if you can find the device in the System Information window that opens.

You haven't specified the model of your adaptor, but you might find drivers here: https://digitalyachtamerica.com/usb-drivers/

You might also find this thread helpful: https://forums.ybw.com/index.php?threads/455598/