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Questions tagged [serial-port]

A hardware interface commonly found on older PCs, usually with a 9-pin DE-9 socket/plug, on networking devices or servers also with RJ-45 socket/plug (otherwise commonly used for ethernet), or with a (much wider) 25-pin DB-25 socket/plug. Two common standards used with such an interface are RS-232 or RS-422.

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No login prompt from Getty over serial console

My Ubuntu 20.04 system has a serial port over which I would like to provide console access. I can confirm that I can communicate over the serial port with sudo picocom -b 115200 /dev/ttyS5 I start ...
1 vote
1 answer
33 views

Serial console changes parameters when SUDOing

I'm working on a project where I need to connect a very old serial terminal to a linux device (a Raspberry). The terminal uses 4800bps, 7 data bits and even parity. I have reconfigured the kernel ...
1 vote
0 answers
104 views

Timed out waiting for device /dev/ttyNVT0

I want to make a physical remote serial port for my server that lets me use this port as a server serial console (this is for retro computer related hobby). I'm using a MikroTik router with its serial ...
8 votes
2 answers
3k views

Switch tabs in Debian installer over serial console with PuTTy

I'm currently trying to install Debian on a system with no video output. All I have is serial console. I know how to get it started and all, and even made it install automatically with a preseeded ...
76 votes
10 answers
188k views

How to bind USB device under a static name?

I have an Arduino which sometimes gets bound to /dev/ttyUSB0 and other times to /dev/ttyUSB1, making my script fail. I do not want to enumerate all the possibilities of where my device could be, but ...
1 vote
1 answer
2k views

udev rules to assign/restrict serial ports to a range of numbers

I'm trying to segregate serial ports based on the manufacturer attribute ATTRS{manufacturer}. I would like to assign /dev/ttyUSBx to those detected as from manufacturer A, where x can take a value ...
0 votes
1 answer
111 views

Armbian enable UART2 for TX/RX

I'm trying to use the UART1 and UART2 of my device (a NanoPi NEO) to read serial data. So far, UART1 i fully functionnal and I can read and transmit data through /dev/ttyS1. I've enabled UART2 using ...
1 vote
1 answer
3k views

Debian not recognizing my ttyS0 / console redirection not working

I have a fitlet2 (https://fit-iot.com/web/products/fitlet2/) which has a serial port. I can connect to the serial port of the fitlet2 with screen from my computer (screen /dev/ttyUSB0 115200) and ...
1 vote
1 answer
1k views

socat: call from script, bashrc or systemd?

I want to use socat to direct serial commands over ethernet to an ethernet-serial converter (static IP address).  I am wondering what would be a good way of starting socat. As I understand it, systemd ...
7 votes
1 answer
9k views

cat: /dev/ttyS0: Input/output error

I am unable to write to or read from /dev/ttyS0 # cat /dev/ttyS0 cat: /dev/ttyS0: Input/output error the device exists, and root has permissions. # ls -lAhF /dev/ttyS0 crw------- 1 ...
63 votes
10 answers
259k views

How can I monitor serial port traffic?

Is there any port monitoring tool to watch the packets written on the port? I especially want to check if my program written in Java works so I need some kind of tool to see if my little application ...
1 vote
1 answer
2k views

Heartbeat not working. Port not opened

I have been trying to place two virtual machine with heartbeat. osboxes and osboxes2. When I run nmap localhost this is the output: Nmap scan report for localhost (127.0.0.1) Host is up (0.00017s ...
2 votes
2 answers
7k views

Intercept communications on physical serial port using socat

I'm no Linux expert so please go easy ;). Ok, the situation is that I have a single board computer running Debian Wheezy. I know its old/risky etc etc but its not actually "my" equipment and ...
0 votes
1 answer
4k views

Android Serial Port is being used for no permission to open

I have a Wandboard IMX 6 with Android OS. I can't read RS232 data. I was wrote an app for this on QtCreator with C++. I have an issue. When i pressed the connect button i take serial port is being ...
1 vote
0 answers
46 views

How to make a virtual tty (tty0tty) look like a real serial port?

I'm using tty0tty. The virtual serial ports appear as /dev/tntX where X is an integer between 0 and 7. Problem is, many apps require "real" serial ports, such as lightburn. So /dev/tntX ...
4 votes
1 answer
2k views

How to bind arduino as a fix block-device --- /dev/ttyACM0?

I want to bind my Arduino Mega as /dev/ttyACM0. Sometimes, it turns out to be /dev/ttyACM0 and sometimes as /dev/ttyACM1. I have taken help from this question and this tutorial Someone please help ...
6 votes
1 answer
433 views

How do I spoof different device ID for the purposes of Linux device management?

I have a WWAN device, which I foolishly bricked by overwriting vendor and product ID (VID and PID) using AT command. I did it in hopes to get around the laptop whitelist feature, which prevented ...
1 vote
1 answer
2k views

How to get a serial terminal emulator in linux to ignore RTS & DTR?

I purchased a generic 8-pin ESP8266 off Amazon. It came loaded with some "AT" command firmware that acted like a modem. I connected the module to an FTDI1232 which is a USB connected UART that acts ...
0 votes
2 answers
4k views

ttyACM0 connected but not showing received data

I have a STM32F4 microcontroller, with the USB interface, I connected it to the raspberry pi. When connected, it shows up as /dev/ttyACM0. I send some chars every second from the device. In windows, ...
0 votes
1 answer
3k views

Send binary file to ttyUSB0 serially in linux

I have a binary file(obtained from assembly code). I need to transfer this file to an fpga serially via ttyUSB0. I read in some posts that using cat and echo data can be transferred to ttyS0. echo -...
0 votes
2 answers
325 views

Serial Port: characters consistently lost when receiving data

I am using Ubuntu 20.04 on Raspberry Pi 4 I am receiving data from another device through USB initiated as serial port with ftdi_sio with udev rules: ACTION=="add", \ ATTRS{idVendor}=="...
0 votes
2 answers
146 views

I would like to find a way to match the output of lsusb to the /dev/ttyUSB* names

Faced with: root@conserver01:/home/owen# lsusb -t /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/4p, 5000M |__ Port 1: ...
29 votes
3 answers
72k views

How does cat know the baud rate of the serial port?

I regularly use cat to view debugging information in the console from my FPGA development board over the serial connection, but I never have had to tell linux what the baud rate is. How does cat know ...
0 votes
0 answers
148 views

using socat or stream to read from serial?

I am trying to send a binary file from Raspbian to an ESP32 device on a RPI USB port, and read response data. I can cat file > /dev/ttyS0, but obviously ">" discards output from the ...
0 votes
0 answers
40 views

Log input to serial port during boot

I have a LCD screen that is connected to the /dev/ttyS0 serial port. During startup, the LCD screen displays gibberish without reason (nothing is written to it). This happens during the very early ...
0 votes
1 answer
3k views

Sending serial data to a USB port from the terminal?

I have an Arduino connected to my USB port (on my Linux based OS) at /dev/ttyACM0 which is listening for serial data to be read and processes them when received. All I need to do is send data to this ...
3 votes
3 answers
9k views

How can I create a virtual serial port that relays data over ssh?

I have a serial port on a remote linux box which I can access over ssh. I would like to create a file (not a real file, maybe a device file or unix domain socket?) which when written to writes to a ...
1 vote
1 answer
140 views

Connecting a Mac to Ubuntu server with a serial port

I have a USB-to-Serial converter for my Mac I want to use to connect to an Ubuntu server that outputs all its console over its serial port (it's an APU2 machine with no graphics output). On the server ...
0 votes
0 answers
18 views

Why error this code of GobiSerial?

this code of GobiSerial driver, however when I load and using dmesg to check => it show error sending startMessage Why nResult error?
4 votes
3 answers
9k views

How to set /dev/ttyUSB device on a specific constant device number?

I use several Linux servers hosts, in which multiple serial-to-USB links are plugged in. They look like /dev/ttyUSBx devices, where x is a number starting from 0. Client devices are often rebooted or ...
0 votes
1 answer
435 views

Virtual COM port using only USB cable

I have seen that it is possible to connect two computers by USB cable and make a virtual ethernet bridge or something like that. My question is, can we do something similar but configure the ...
0 votes
1 answer
212 views

ttyUSB ordering

I am working on a project involving the development of a device that interfaces with multiple ttyUSB ports, specifically 16 of them. It's important to note that Linux handles ttyUSB ports differently ...
1 vote
2 answers
635 views

Serial port's modem lights up, but can't communicate

My MB has builtin UARTs (Supermicro X10SAE). I've got an external modem hooked up to /dev/ttyS0. I'm running CentOS7. Without minicom running on /dev/ttyS0: The modem has CTS on. With minicom ...
1 vote
0 answers
211 views

Why are serial ports losing bytes after Linux upgrade?

I have an embedded Linux system built using Yocto. Recently I upgraded from Dunfell (kernel 5.4) to Kirkstone (kernel 5.15) and I started having problems with the serial port. Large chunks of bytes ...
0 votes
3 answers
275 views

How to patch kernel to reduce VTIME gap for uart termios API?

I need help to find a kernel patch to get a VTIME from tty termios API lower than 100ms, in order to decrease gap inter char. It blocks read syscall until VTIME timeout. Function n_tty_read() is the ...
1 vote
0 answers
93 views

How to read elm327 obd2 raw data over bt using rfcomm?

I am trying to read my car data, i have hooked a cheap elm327 bt obd2 connector to it, and using lubuntu. Basically this is what i have done, but its not fully working i end up with a sort of buggy ...
0 votes
1 answer
291 views

Pseudo terminal for comms between two processes

I am writing an executable that uses a 3rd party C library (libmodbus if it matters) to communicate via serial device (in my case, /dev/ttyUSB0 or similar to talk RS-485 via an FTDI chipset based USB-...
0 votes
2 answers
164 views

Help opening USB serial link

My goal is to talk to an ARM mmc through a Segger serial link using this command: python3 -m serial.tools.miniterm -e /dev/ttyUSB3 115200 However, I get the following error message: No such file or ...
9 votes
5 answers
62k views

Find and kill the process that is using a serial port

I have multiple serial ports to each of which devices are connected. They are listed as /dev/ttyUSB*. Now, I need to make sure using a python script that no other process is using any of these before ...
2 votes
1 answer
10k views

udev rules for USB serial 'by path' not working

I have more than 2 serial devices enumerated by FTDI driver as /dev/ttyUSB0, /dev/ttyUSB1, /dev/ttyUSB2 etc. On reboot, these may get jumbled up in any other order. Also, I may replace/swap these ...
0 votes
0 answers
314 views

Troubleshooting Communication Issue between Jetson Nano (Linux) and RS485-USB Converter in linux

I'm encountering a communication problem between my Jetson Nano (running Linux) and an RS485-USB converter. I'm seeking assistance in resolving this issue. Below are the details: I'm using the ...
2 votes
1 answer
252 views

GRUB2 serial console issues on NVMe-based pc

I want to interact with GRUB through a usb-to-serial converter. I was able to achieve this on my laptop by using this list of commands in grub's cli: insmod nativedisk #to not loose drive information ...
1 vote
1 answer
2k views

Unable to write/read from serial port after couple of minutes/hours. Error message: stty: standard input: Inappropriate ioctl for device

I am trying to write and read from serial port at the same time. The purpose of this is to turn on and off a device over a DIO card which is connected to the serial port. While doing these on/off test,...
0 votes
1 answer
166 views

Accessing two linux systems using one serial console port one at a time using splitter

I have two linux devices with serial console port. I have only one serial port on terminal server and i want to access both these devices one at a time basis. Can i hub/ splitter do the task if i ...
74 votes
5 answers
553k views

How to send data to a serial port and see any answer?

On Linux, I want to send a command string (i.e. some data) to a serial port (containing control characters), and listen to the response (which also usually might contain control characters). How can ...
1 vote
2 answers
2k views

serial port via minicom: can minicom use line-editing (i.e. readline functionality)?

I am successfully talking to a board connected over a serial port interface to my PC. I can both send and receive bytes - but for interactive applications executing on the board, that try to read ...
0 votes
0 answers
644 views

Reset USB serial device as if it has been physically reconnected

I have computers set up, each with a single 3DR/Sik Radio (USB) connected to receive data from a single 3DR transmitter on another machine. When this computer with the transmitting device is rebooted, ...
0 votes
1 answer
527 views

How to change the major and minor number of a device file?

I am currently working with an Embedded Linux Board and need to use the serial port, which is represented by the device file /dev/ttyS0. Upon running the command ls -l, I observed that the major and ...
45 votes
4 answers
158k views

set baud speed for tty

How do I set the baud speed for a specific tty (in this case a serial port)? I tried using stty -F /dev/tty.iap ispeed 19200 But get the error Invalid argument for every speed I try (2400, 4800, ...
2 votes
1 answer
184 views

Where are the hub and serial device drivers in Linux and have you ever seen a serial TTL adapter cut off data after some period of time

This question will be difficult to fully explain, I apologize in advance, but please read the entire description? Thank you. NOTE: I'm primarily posted this to document it, and only asking for advice ...

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