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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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USB cdc_acm driver not assigning Data interface to any port

I have a USB CDC-ACM device emulating Serial over USB communication. The CDC Communications and Data interfaces are shown respectively on 2-1:1.0 (Comm) and 2-1:1.1 (Data) interface descriptors, and ...
Pierre B.'s user avatar
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7 votes
1 answer
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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 ...
Martin Vegter's user avatar
4 votes
0 answers
608 views

Is there a way to change where systemd sends its output during shutdown?

I want systemd to send shutdown messages to a TTY that is different from the one that was used during bootup. More specifically, if the system starts to shutdown, the system should send any messages ...
Tenders McChiken's user avatar
4 votes
0 answers
305 views

Listening on the data between a process and a serial port

I have a process that is using /dev/ttyAMA2 port to communicate with an external device on a PCB. What options do I have of listening to the communication between a process and a serial port, on an ...
CodeBreaker's user avatar
4 votes
0 answers
1k views

slow file transfer through serial port with cat

I'm transferring a binary file to an embedded device using a custom AT command set. I'm running Lubuntu Linux on a virtual machine (Windows 7 host) and the virtual linux guest controls the physical ...
user176030's user avatar
4 votes
0 answers
2k views

How to send AT commands to serial interface in Yocto Linux?

I have a XBee device attached to the ttyMDF1 interface on an Intel Edison board running Yocto linux. I need to configure the XBee by sending AT commands to it. I have tried to open a getty /dev/...
Jesus Garcia's user avatar
4 votes
0 answers
1k views

Find a IR transmitter device

I would like to use the IR transmitter included in a cubox. I did not found any documentation to use it, so I would want to learn how to communicate with periphericals on linux. Commands like lshw,...
Gaël Barbin's user avatar
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 ...
Am_I_Helpful's user avatar
3 votes
0 answers
2k views

USB gadget serial-port (g_serial or composite): how do I control what name Windows will see?

I'm trying to add a gadget-serial interface to my project, either by way of modprobe g_serial or by way of a composite/configfs method. I have a little script (shown below) that works perfectly when ...
Nicholas Clark's user avatar
3 votes
0 answers
4k 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.
Dims's user avatar
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3 votes
0 answers
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Access one Serial Port with two Python Scripts

I am trying to access one serial port (/dev/ttyACM0) on my Rasbperry with two Python scripts, which obviously doesn't work because one blocks the other. The thing is that one script only needs to read ...
Philipp's user avatar
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3 votes
0 answers
266 views

MSI interrupt in serial driver

This is a more general question: I have a RS485 PCIe card in my system (PERICOM_PI7C9X7954). The driver for it is in 8250_pci.c. It configures the PCIe interface. However, it doesn't use the MSI ...
ilya1725's user avatar
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3 votes
0 answers
427 views

Why only 4 chars get sent to serial port via command-line

I'm trying to communicate with NodeMCU (CP210x USB/UART) from command-line. However it does not respond to my commands. I have set the correct baudrate via stty 9600 raw. echo "gpio.write(0,gpio.LOW)"...
Marki555's user avatar
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3 votes
0 answers
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Linux Mint FTDI Usb to Serial Input/output error

I am really frustrated here... My problem is that after some point (at first it worked correctly), a Digi Board I am using (with FTDI chipset) cannot be accessed through the serial (usb to serial) ...
mitsos1os's user avatar
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3 votes
0 answers
1k views

USB to UART converter is lagging

I have a USB to UART converter with CH341A chip on it. This device can be used as a USB to UART converter, as a 24/25 chip programmer and as a USB to PARALLEL converter. The problem is with the UART ...
redbeam_'s user avatar
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2 votes
0 answers
41 views

How to enable the second serial port on old vm AT&T SVR4?

Usually one serial port is sufficient to control via minicom the old SVR4 on Qemu (I know is a very old system, is unsafe, etc..). I have set those two ports on configuration of vm <serial type=&...
elbarna's user avatar
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2 votes
1 answer
327 views

How to log binary data with GNU screen

I am using GNU screen to open a serial port and log incoming binary data to a file. The command I use is: screen -S mySession -L -Logfile data_out /dev/ttyUSB0 115200, cs8 At some point the recording ...
NickG's user avatar
  • 121
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 ...
RobF's user avatar
  • 21
2 votes
1 answer
169 views

How do I send values from both pins of the serial port?

I am trying to intercommunicate my linux system with my microcontroller. I have configured DB-9 pins as full duplex RS485 as below: I have connected Pin-7 with Pin-8. I have connected Pin-2 with Pin-...
Mehmet's user avatar
  • 23
2 votes
0 answers
349 views

How to redirect GRUB2 output to a MMIO serial UART?

Is it possible to redirect GRUB2 output to a MMIO serial UART? For example I have a UART that is displayed in a Linux boot log as: AMDI0020:01: ttyS5 at MMIO 0xfedca000 (irq = 4, base_baud = 3000000) ...
kostr22's user avatar
  • 216
2 votes
0 answers
449 views

Redirecting only whole lines from serial port to netcat

I would like to redirect data from two serial ports over ethernet connection to single port. I've managed to send data, but as serial port data is slow, messages might get corrupted as these does not ...
jaker's user avatar
  • 23
2 votes
0 answers
657 views

Use rs485 driver specifying the DE pin

On an embedded system (STM32MP1 w/ Yocto environment) I need to control an rs485 transceiver. Unfortunately, the DE pin of the transceiver is connected to a generic GPIO pin of the MPU and not to the ...
Mark's user avatar
  • 733
2 votes
0 answers
2k views

device or resource busy: /dev/ttyUSB0 when not root

I've got an arduino that I use echo "b" > /dev/ttyUSB0 to send data to it. When this command is run via the root user it works correctly. However a normal user gets an error of: echo 'b' > /...
Chris Stryczynski's user avatar
2 votes
0 answers
1k views

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 ...
Kamil's user avatar
  • 749
2 votes
1 answer
77 views

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 ...
Guilherme's user avatar
2 votes
0 answers
2k views

/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 ...
Krastanov's user avatar
  • 171
2 votes
0 answers
698 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 ...
Shivaprasad A Prabhu's user avatar
2 votes
0 answers
1k views

How to Verify that a UART is Enabled on a Beaglebone Black

Question Is the existence of a /dev/ttyO* symlink evidence that the corresponding UART device is enabled? If not, how can I check whether or not the UART has been successfully enabled? Details I'm ...
igal's user avatar
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2 votes
0 answers
2k views

GPS device not detected by gpsctl

My GPS device (/dev/ttyUSB2) outputs NMEA sentences when connected to with minicom or cat, but when using gpsctl with gpsd (running gpsd /dev/ttyUSB2) the following output is generated: gpsctl: no ...
user60684's user avatar
  • 1,763
2 votes
0 answers
1k views

Serial console using ttyS5 for EFI boot

I have a host where I run minicom and there is a board with two serial ports (ttyS4,ttyS5). I connect board to host with serial to usb which is identified as ttyUSB0 in my host. When I set kernel ...
arceus's user avatar
  • 21
2 votes
0 answers
972 views

how to enable RS485 of beaglebone black

I am using beaglebone with kernel 4.4. I am trying to use the RS485, with pin 9.11 and pin 9.13 for tx/rx, and pin 9.27 as a GPIO control for the DE/RE pin. I bought a SN65HVD72, and connect it as ...
Peilang Liao's user avatar
2 votes
0 answers
218 views

Detecting when serial RX goes idle between data packets

I'm running an ARM-based computer that receives data from an external device via serial. The external device alternates between bursts of data and idling: 25 bytes, then 3ms idle, 25 bytes, 3ms idle, ...
Dan Laks's user avatar
  • 351
2 votes
0 answers
2k views

Monitoring serial port data between virtual ports

I have a problem with monitoring data transferred between 3D printer and software over TCP. I have 3D printer that is connected to Raspberry pi with usb cable. I'm using ser2net in rasbperry to ...
Toni's user avatar
  • 21
2 votes
0 answers
365 views

Use mgetty to answer a call and press a key

I bought a GSM shield for the Raspberry Pi (version 1, B) and a SIM card to join the proper cellular network. I use mgetty to react to my call, like this: mgetty conf which works just fine and the ...
dolfin's user avatar
  • 21
2 votes
0 answers
2k views

Send data to a serial port via screen

I've connected to a serial port via screen /dev/ttyACM0 and can read the input, but can't see the text I'm typing and nothing is being sent after I press enter. Is it possible to send data from ...
andrey's user avatar
  • 61
2 votes
0 answers
2k views

Polling for Serial Port Information

Firstly, let me preface by saying I feel silly for asking a question like this. The information should be online, but I can't seem to find it anywhere. I feel like I've looked pretty hard, but nothing ...
MD-7's user avatar
  • 193
2 votes
0 answers
1k views

Difference in proper configuration for Windows UART VS Linux UART

Core question: How does UART connection on *nix differ from UART connection on Windows ? What settings need to be kept in consideration for proper data transmission and reception ? Context for asking ...
Sergiy Kolodyazhnyy's user avatar
2 votes
0 answers
1k views

Working /dev/ttyS0 but can't transfer binary (one serial but two drivers Com1/Com4)

I think it's a driver config issue, it works in winXP(dual boot) with intel drivers. I'm debugging via serial port from another machine, which works fine. The PC is a i5 dell Optiplex 790 running ...
Ben.M's user avatar
  • 21
2 votes
0 answers
1k views

How to change 'Input Buffer Size' setting in Minicom

I'm using minicom to interface with a bluetooth device. I have been able to successfully do this in matlab, however I have to first change the 'InputBufferSize' parameter in matlab from 512 to 24 ...
alittletouched's user avatar
2 votes
0 answers
545 views

Disable and enable reading from touch-screen's serial port

I have X server configured to work with a touch screen through the egalax driver and a serial port. [xorg.conf] Section "InputDevice" Identifier "EETI" Driver "egalax" Option "Device" "/...
aloplop85's user avatar
  • 205
2 votes
0 answers
299 views

How to enable fifth serial port on Debian 7

I have put a fresh install of Debian 7.9.0 on an ASRock IMB-150 mainboard and only 4 of the 5 on-board serial ports seem to be enabled. root@myhost:~# dmesg | grep tty [ 0.000000] console [tty0] ...
Guy's user avatar
  • 331
2 votes
0 answers
1k views

How to configure USB serial port paramters for a Windows program running in Wine?

I have a small CNC machine that's controlled by a custom piece of Windows software over USB, and I'd like to be able to run it from Linux. The software loads up fine under Wine, but it can't see the ...
Erik's user avatar
  • 121
2 votes
0 answers
570 views

USB / RS485 converter static mapping to /dev/ttyUSB

I need to map one serial port converter to static usb port so after my raspberry gets restarted I still have the right mapping. I bought this USB-> serial port RS485 converter http://www.dx.com/p/usb-...
Simon's user avatar
  • 45
2 votes
0 answers
1k views

Send message to Android phone using bluetooth

I have a Raspberry Pi which you can assume to be just a Linux machine. It runs BlueZ and is successfully paired with my Android phone. What I want to do is, my Python program should be able to send a ...
bfrgzju's user avatar
  • 209
2 votes
0 answers
1k views

Transfer file to pc from embedded linux device via serial communications

I'm working on an AT91SAM9G20. I'm connected to AT91SAM9G20 via the debug port using rs232 serial communications. It has Linux version 3.4.8 but does not appear to have any of the common file ...
SeanJ's user avatar
  • 167
2 votes
0 answers
5k views

cat /dev/ttyS0 Input/output error

I created infrared receiver as in LIRC manual (http://www.lirc.org/receivers.html). And tested it on windows using program called Terminal. When I switched on RTS pin DCD pin was also switched on ...
piotrekkr's user avatar
  • 569
2 votes
0 answers
2k views

How to setup ssh over USB on an embedded linux device?

I have an embedded linux device with an ARM processor. I am connecting to it over a USB port using minicom. What should I do to "ssh" into the device through the USB connection? I want to setup ...
Nithin's user avatar
  • 473
2 votes
1 answer
1k views

VT100 terminal emulation to use with a Java-based 8-bit computer emulator

I'm successfully using GNU Screen as serial terminal to "talk" to my Altair 8800 clone (http://altairclone.com/) using serial line. The command I use is: screen -istrip /dev/ttyUSB0 Screen does the ...
user72879's user avatar
2 votes
0 answers
529 views

Strange behaviour using serial port and bluetooth

I'm trying to connect via serial port, a wearable device to a processing IDE using a Bluetooth connection on Linux Mint. I've got the connection part working, but the problem is that the connection is ...
Rafag's user avatar
  • 121
2 votes
0 answers
1k views

Kicking a process from a USB-Serial port

I have a application which is using the USB-serial port. Occasionally on shutdown the port cannot be opened by another instance of the program, and up until now the only way I know of the program ...
John's user avatar
  • 121