TTY device usable only once after being connected on the Jetson AGX Orin


I have a connection issue with a barcode scanner connected by usb to the Jetson Orin. Right now, when I first connect the scanner (MS4717) everything works fine. I can run my project or any tool interacting with the device for as long as I want. But if I quit and restart the project or any of the multiple tools I have tried, the Jetson is no longer receiving any data from the scanner.

The scanner is always mounted correctly (usually at /dev/ttyACM0) and communicates by SSI over USB CDC. I’ve tried monitoring with pyserial’s miniterm and with screen /dev/ttyACM0 9600 but the same problem arises, if I ever stop the program I can’t connect to the scanner anymore afterwards (f.e. screen just says [screen is terminating])

I haven’t encountered this issue on any other computer, so I believe it might be an issue with the Jetson rather than the scanner.

In the project I’m trying to run, I use pyserial to interact with the device. Here is an extract of the code to give you an idea of how I use it:

import serial
serial_port = "/dev/ttyACM0"
baud_rate = 9600
 with serial.Serial(serial_port, baud_rate, timeout=0.1) as device_serial:
            while True:
                    # read a line from the serial port
                    barcode_byte_string = device_serial.readline()
                    if len(barcode_byte_string) > 0:
                        # convert the byte string to a string and strip the newline character
                        barcode = barcode_byte_string.decode("utf-8").rstrip()
                        # publish the barcode to the topic
                        self.publish_barcode(barcode, serial_port)
                except serial.SerialException as e:
                    # exit with error code 1. This will cause the application to be restarted.
                except Exception as e:


hello user50680,

could you please have a try to disable getty service.
for example,
$ sudo systemctl stop nvgetty.service
$ sudo systemctl disable nvgetty.service

Hi JerryChang,
I’ve disabled getty service, but sadly it didn’t solve the problem

hello user50680,

actually, /dev/ttyACM0 is used by Orin as combined uart for sending logs.
how you connect your barcode scanner, had you tried connect it to Orin platform after system boot-up?

I don’t seem to have anything on /dev/ttyACM0 at startup, unless I have the barcode scanner already plugged. Here is a screenshot of my /dev/ folder:

hello user50680,

as you can see… USB micro-B for Debug UART.
you should see that node created after you connect the port to monitor the Debug UART.

I can see the four devices mounted as /dev/ttyACM[0-4] on the host pc, but nothing new appears on the Orin

I am still experiencing the same issue. I tried using a different barcode scanner and the same issue still arises. Is there a known communication problem between arm64 devices and tty devices that could be the reason?

It seems the problem happens only on the Jetson Orin, I was able to use the same barcode scanner without issues on the Jetson AGX Xavier with the same JetPack 5.0.2

hello user50680,

could you please see-also this topic, Topic 239735.
this looks like similar issue with USB to TTY stability on AGX Orin.

is it possible to configure two stop bits for checking?


We have solved the issue by connecting the barcode scanners to the Jetson through the PCIe port, everything works as intended now.
The issue probably came from the USB controller, we have ordered a second Orin AGX to test if the problem is particular to the unit we got.

I will look into configuring the two stop bits in the future, and will keep you updated.

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