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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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tcpdump usbmon module output explained

Running the command: tcpdump -qAXni usbmon3 -s 0 I am getting this output: 02:32:04.781964 BULK SUBMIT to 3:16:4 What does the last number after the colon (4) represent? How can I identify it in ...
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gpsd works only once

I am working on connecting a Garmin Oregon 750 GPS to a Linux box using gpsd. The final goal is to use it for navigation inside Qgis. So far I've managed to make it talk to the computer using gpsd, ...
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Serial port program to write file/read to file from tty?

i'm looking for some commandline program which I can use to send and receive data to/from serial port. I would like to automate my testing process - start test script which will send file to ttyPC, ...
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Chained serial connections to Linux machines with picocom and screen issues

I am connecting via serial terminal (picocom) to a Linux machine which at the same time has several serial interfaces I want to use. In that Linux machine I can only use screen to do so. My problem is ...
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Listen in to data read from file descriptor to ttyS

I have a serial device under /dev/ttyS0 and an application that is reading from the serial device (but not writing to it). I wanted to listen in to the data that is coming in on the serial device but ...
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Assigning users to serial device server

I'm working on a server (CentOS 7) that will be connected to a serial device service. I also have 6 client machines. The SDS makes the devices show as actual devices in linux and can be controlled by ...
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43 views

create pty and connect it to a serial port /dev/ttyUSB0

Problem: I have two Linux machines connected with a serial interface. I use ppp to communicate between them (I have to since it is a project requirement). Communication speed is at 9600 bits/s. I ...
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SER2NET “Tee or Wedge”

I am successfully using SER2NET on a Raspberry Pi to translate RS-232 data to Ethernet. But I would like to "watch" the data coming from the serial port for a certain string, and if there is a match, ...
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126 views

Virtual serial port between docker containers

I can create two linked virtual serial ports on a Linux system with socat, and pretend one end is a serial device, and the other one is some code that uses the device. The socat command would look ...
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99 views

How to have local echo on with `screen` command?

I tried screen /dev/ttyUSB1 9600,echo but I still don't see what I type.
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30 views

Turning USB into a terminal

I have a hardware device that connects via USB without creating a specific /dev/something. It does change the time on /dev/ptmx and /dev/char but that's about it. All I know are the VID:PID of the ...
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124 views

Dpkg-reconfigure openssh-server fails on boot

When I boot the linux, dpkg-reconfigure openssh-server fails and the booting gets stopped there. But when i press ctrl+c it resumes the booting with dpkg-reconfigure failed.
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How to use Libudev to find out which ports are connected to my Usb

I made a kind of module. Different sensors are placed in the module. I connected the module to Raspberry Pi through RS232 converter. I am using Libudev to automatically find out which Pi port has ...
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Is there any standard for naming RS-485 tty devices/device aliases in Linux?

I know, that there are some standards in tty naming. There is ttyUSBx for USB to serial converters, ttySx for RS-232, ttyAMAx on ARM devices, but I can't find anything about conventions in RS-485 ...
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1answer
38 views

UART to UART tcp/ip connection

Need to transmit and receive data(TCP/IP) between 2 raspberry through serial tx/rx pins (/ttyAMA0). Best way to do it? Better if this will be done from kernel space. Thanks!
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1answer
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How do I use jpnevulator to capture and log the serial traffic between an application and hardware serial port?

OK, I've been googling for hours so I obviously have not been able to understand the answers to the various questions that have already been asked about this subject. I am hoping that, by asking the ...
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131 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 ...
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1answer
183 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 ...
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76 views

Getting rid of a serial console on Respeaker Core V2

I have a Respeaker Core v2.0 and I would like to use the UART interface (this board has a USB to TTL adapter connected to the Uart port) in order to make this board communicate with another one. ...
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1answer
101 views

ppp between two machines over serial without a modem

Moving question from stackoverflow.com Unfortunately can't delete this question from stackoverflow.com. I'm trying to setup a PPP connection between two Linux machines over a serial line. I followed ...
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1answer
114 views

How to send F10 with gtkterm?

How can I send F1..F12 especially F10 in gtkterm? I have to press F10 at the right moment to select the boot menu of an APU2 system.
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102 views

Do “serial ports” or “parallel ports” apply to character devices only, but not to block devices?

From http://haifux.org/lectures/86-sil/kernel-modules-drivers/node10.html A Character ('c') Device is one with which the Driver communicates by sending and receiving single characters (bytes, ...
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75 views

libvirt and kvm/qemu, password on console redirection/serial doesn't work

I have added a serial,and a console to connect my vm without X using this command. virsh console myvm Unfortunately my vm has a luks encrypted root and..I can put the password only from graphical ...
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285 views

resetting serial port configuration

stty allows to read a serial port configuration. I have noticed that when some program opens, configures and later closes a serial port the last serial port configuration is still present in the ...
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1answer
285 views

sniffing serial port - jpnevulator sniffs only some bytes

I use jpnevulator to sniff an application which reads a serial port: jpnevulator --tty /dev/ttyS0 --read Let's assume that the following bytes are sent to the serial port: A B C D E. Sometimes ...
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1answer
97 views

Send program's serial output to pseudo-terminal used by serial sniffer such as jpnevulator [duplicate]

I am running an application that communicates through a real serial port e.g. /dev/ttyS0 to a remote device. I can configure this application to use /dev/ttyS0, /dev/ttyS1, etc., by passing the ...
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1answer
58 views

Troubleshooting an RS-485 communication

I have an ND-6021 Analog Input Module. It is an RS-485 device that can set a variable output voltage based on the command it receives. I am trying to make it works under a Linux Debian Stretch. I have ...
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18 views

Why serial of libvirt using pts/* is avaliable only to root?

I have a old vm,no networking(sic!) so I use the old good serial for comunicate from host. On libvirt/qemu is possible to setup a pseudotty pts like a real serial port. Serial is ok on guest,on host ...
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1answer
88 views

Knowing when a write() on a serial port has finished transmitting data

I need to synchronize an IO pin value with a write to a serial port from user space (because I wasn't yet able to do it from kernel space - see my other question). My code (leaving out error checking) ...
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1answer
80 views

Hardware controlled RTS on tty

I have a UART whose RTS pin is connected to an external RS485 transceiver, so that asserting the RTS pin would set the transceiver to send mode. I thought I could configure the serial port to use the ...
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205 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 ...
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1answer
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Thermal printer only print after send a second output data to tty port

I have a PCI Serial Card installed on a POS computer and I'm trying to install an old thermal printer in it. The test command ls > /dev/ttyS4 works well, but only after the second time I send it. For ...
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/dev/tty* serial devices are in group “root” for a second before they are switchted to group “dialout”. How to make them start out in “dialout”?

When I plug in a usb-to-serial device, it takes some time for the device to be switched to the "dialout" group (it starts out in the "root") group. This wreaks havoc with some client software that ...
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1answer
26 views

Has the /sys/bus/usb/ the same structure in all Linux distributions

I am porting mono app from Windows to Linux. The app communicates with external board. This board is visible as three virtual serial ports. Every plays a different role. The app is automatically ...
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125 views

Open serial port ttyACM* from Minicom

I'm working on one issue where data transfer over ttyACM* is always success when that particular ttyACM* is kept open from Minicom/Putty application. My Device runs with DWC3 Synopsis USB driver ...
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How to recompile and run a prebuilt linux kernel driver as a custom module?

I am able to create a custom basic module (hello wrold kernel) and use insmod to load it into kernel space. However what I need now is to be able to use slip.c code by its entirety (copy and paste) ...
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1answer
139 views

Serial port ignoring custom divisor

I am trying to run a serial port at 3.25Mb/s by applying a divisor of 2 to a baud base of 6.5Mb/s. I am using an IoT device (Telit HE922-3GR) running android 6 with built in serial ports, the proc/tty/...
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1answer
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LoRaWAN wireless dongle not responding to AT command [closed]

0 down vote favorite I want to configure a wireless LoRaWAN dongle via AT commands by using the echo command in the ubuntu terminal but the dongle doesn't seems to be responding with any feedback ...
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137 views

Why does my serial port give a response without a loopback cable?

I'm new to using serial ports, and I have a loopback cable for serial on a Centos 7 machine. I have something in python that tests the port, but I've found that the program returns the expected ...
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2answers
371 views

Retrieve file over serial without kermit and lrzsz

I have an embedded Linux on a custom board and I would like to send and receive file over its serial port. The only way to communicate with this device is over serial and the device offers a console ...
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2answers
80 views

How to give a tty a mode other than 640 and have it persist through reboot

I have an embedded device (Nvidia Jetson TX2 running Ubuntu 16.04) in a carrier board and need to use the serial port. The serial port on the carrier board maps to ttyS0 which by default is owned by ...
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Disable a single USB port not all and enable it after 30 seconds after boot [duplicate]

I want to disable some USB Port,I mean that on every boot the system should not recognize if there is a device connected to the port. and after that there is a Bash script that run on every boot to ...
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115 views

Difference between eof=^A and eof=^D of stty command

I would like to know the difference between eof=^A and eof=^D which will be displayed when stty -a command is given. Also is there any command to change it from eof=^A to eof=^D?
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19 views

Data loss over ttyACM* in Ubuntu 14.04 whereas success on Ubuntu 16.04 when “cat” command is used [duplicate]

I have a development board which will have 3 ACM interfaces when connected to Ubuntu host and i want to transfer data from Host to Device over ttyACM3. I have followed the following procedure for ...
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PING token missed after un-successful Bulk OUT transfer

I'm trying to send a large amount of data(~15 Mb) from Host to Device over ttyACM3. I have used "cat" command for sending the data from host. Host side: cat ./pattern.bin > /dev/ttyACM3 Device ...
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139 views

Data loss over ttyACM* when 'cat' command is used for data transfer

I have a development board which will have 3 ACM interfaces when connected to Ubuntu host and i want to transfer data from Host to Device over ttyACM3. I have followed the following procedure for ...
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1answer
434 views

picocom - how to read hex bytes

I use picocom to read a serial port. I try to display hex bytes this way (man): picocom --imap ???hex -b 19200 /dev/ttyS0 But it doesn't work. What is wrong?
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134 views

bridge between UDP and serial doesn't work

I've created a bridge between UDP and serial port using socat. Here is what I have socat -xv udp4:localhost:54321 open:/dev/ttyUSB1,rawer,lockfile=/tmp/s1.locak,echo=1,b115200,crnl To monitor ...
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1answer
2k views

create a UDP to serial bridge with socat

I have a piece of software that transmits data over a UDP connection. However in our system we can transmit data only over a serial port. I was thinking of making a bridge between a UDP and serial ...
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1answer
762 views

Can't read serial data from /dev/ttyUSB0

I am using an RS485 to USB adapter in order to communicate with hardware, whose parameters can be changed by sending data strings in hex. I set: sudo chmod o+rw /dev/ttyUSB0 stty -F /dev/ttyUSB0 ...