MacArthur Hat Serial Connection Question

[fourfun]

Hi,

  Can anyone help me identify what a mysterious second tty port is?

I just got a new MacArthur Hat and a new MAIANA kit.  I hooked everything up and used an Ethernet cable to connect to the MAIANA antenna to the MacArthur Hat.  When I launched the serial app and activated UART0 there were two tty devices available in the serial app, ttyAMA0 and ttyAMA10. The MAIANA kit works fine set up on ttyAMA0 and is communicating with SignalK and OpenPlotter, so no issues.  I would just like to know what the second tty port is. 

Setup:
Raspberry Pi 5
MacArthur Hat (new)
MAIANA Kit (HW 11.9.1 FW 4.4.1) connected to ttyAM0

Thanks,
Charles

[Sailoog]

[fourfun]

I'm glad we have smart people out there!  Thank you.