Try /dev/ttyUSB0 and see if that works The dmesg command will tell you which device is attached.
Here is the output for my pi4, which uses a pl2303 serial/usb adaptor to connect to a Davis serial logger. pi@pi4:~ $ lsusb Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port / Mobile Action MA-8910P <==== Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub pi@pi4:~ $ dmesg | grep -i usb [ 1.853807] usb 1-1: new high-speed USB device number 2 using xhci_hcd [ 2.036438] usb 1-1: New USB device found, idVendor=2109, idProduct=3431, bcdDevice= 4.21 [ 2.036495] usb 1-1: New USB device strings: Mfr=0, Product=1, SerialNumber=0 [ 2.036530] usb 1-1: Product: USB2.0 Hub [ 2.039321] hub 1-1:1.0: USB hub found [ 2.363822] usb 1-1.3: new full-speed USB device number 3 using xhci_hcd [ 2.510398] usb 1-1.3: New USB device found, idVendor=067b, idProduct=2303, bcdDevice= 3.00 [ 2.510458] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 2.510499] usb 1-1.3: Product: USB-Serial Controller [ 2.510530] usb 1-1.3: Manufacturer: Prolific Technology Inc. [ 6.685846] usbcore: registered new interface driver brcmfmac [ 6.767495] usbcore: registered new interface driver usbserial_generic [ 6.767732] usbserial: USB Serial support registered for generic [ 6.828565] usbcore: registered new interface driver pl2303 [ 6.828727] usbserial: USB Serial support registered for pl2303 [ 6.898445] usb 1-1.3: pl2303 converter now attached to ttyUSB0 <========= So for my system using a pl2303 serial to usb adaptor: port = /dev/ttyUSB0 (apologies if any translation of this gets garbled) -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/28b3f487-0764-43ab-9433-1341c8245633n%40googlegroups.com.