Cannot connect to KNX bus via FT1.2

Dear ALL,

Could you pls assit me to connect my OpenHab to KNX bus via serial (/dev/ttyACM0).
In brief - I have a TPUART connected to USB and it gives me a /dev/ttyACM0 serial device.
But OpenHab canot connect to the device: "Could not initialize class " and “Serial port ‘/dev/ttyACM0’ could not be opened”

I’ve spend some days trying to solve issue but failed. May be I’m doing something wrong.

Here are some logs & printouts from my server:

Thanks in advance,




Jan 7 19:14:08 nuc[25573]: java.lang.NoClassDefFoundError: Could not initialize class thrown while loading
Jan 7 19:14:08 nuc[25573]: 19:14:08.793 [ERROR] [b.k.i.connection.KNXConnection:225 ] - Error connecting to KNX bus: Serial port ‘/dev/ttyACM0’ could not be opened. Available ports are:
Jan 7 19:14:08 nuc[25573]: 19:14:08.793 [INFO ] [b.k.i.connection.KNXConnection:488 ] - KNX link will be retried in 60 seconds
Jan 7 19:14:08 nuc[25573]: 19:14:08.794 [INFO ] [ :51 ] - [Timer-5] FT1.2 /dev/ttyACM0: open rxtx library serial port connection
Jan 7 19:14:08 nuc[25573]: 19:14:08.798 [WARN ] [ :49 ] - [Timer-5] FT1.2 /dev/ttyACM0: rxtx serial port access failed


Bus 002 Device 005: ID 03eb:204b Atmel Corp. LUFA USB to Serial Adapter Project

ls -l /dev/ttyA*:
crw-rw---- 1 root dialout 166, 0 Jan 7 19:13 /dev/ttyACM0


[ 2655.937873] usb 2-1.1: new full-speed USB device number 5 using ehci-pci
[ 2656.032463] usb 2-1.1: New USB device found, idVendor=03eb, idProduct=204b
[ 2656.032474] usb 2-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=220
[ 2656.032479] usb 2-1.1: Product: TPUART
[ 2656.032484] usb 2-1.1: Manufacturer:
[ 2656.032488] usb 2-1.1: SerialNumber: 854393439393517141E1
[ 2656.048210] cdc_acm 2-1.1:1.0: ttyACM0: USB ACM device
[ 2656.048573] usbcore: registered new interface driver cdc_acm
[ 2656.048579] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters

groups openhab:

openhab: openhab dialout

ttyACM0 is no standard serial port, so, you have to declare this port at openHAB startup. See for details.
This is for openHAB1, but AFAIR this belongs to openHAB2, too, with a different way to set up.

Ah, sorry, did not see, you already did this…