Linux usb to tty

How do I connect to TTY/COM (/dev/ttyUSB0)?

I am running Ubuntu for the first time by booting from a USB drive. Now I have plugged in a USB-to-serial converter which has been recognized and automatically added as /dev/ttyUSB0 . How do I access /dev/ttyUSB0 ?

11 Answers 11

Use one of screen’s lesser known features:

if you need to specify the baud rate, add it after the serial device. eg, for 57600 baud: screen /dev/ttyUSB0 57600

Note that if you want to detach from the terminal and CTRL-D isn’t cutting it, use CTRL-A then k to kill screen. I had to use this with the TTY at ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty provided by Docker for Mac. CTRL-A then d will work too, but will leave your screen session running, which may or may not be what you want.

Most people using this will also want to specify -ixon: screen /dev/ttyUSB0 115200,-ixon . If this isn’t specified and the remote device ever sends a 0x13 (^S), screen will start buffering everything you type and it won’t send it until the remote device sends a 0x11 (^Q). See info screen ‘Window Types’ for more on this.

busybox microcom -t 5000 /dev/ttyUSB0 

You could use tio — a simple tty terminal I/O application:

You can use picocom, it is a minimal dumb-terminal emulation program. Basic usage is something like this (change 11520 to the desired baud rate):

$ picocom -b 115200 /dev/ttyUSB0 

You have all the options you may want from a dumb-terminal program, like stop bits, parity, local echo, carriage return / line feed / backspace / delete / tab translation, X/Y/Z-modem and ASCII transfer integration, etc.

See man picocom and picocom —help for further information.

you can use ckermit also. It should be in the repository. After installing it create a file in your home directory called .mykermrc then add the 5 following lines:

set line /dev/ttyUSB0 set flow-control none set carrier-watch off set speed 115200 connect 

parameters can be adjusted as necessary.
save the file.
to start it

You can use putty. Its an ssh/serial/telnet client for Windows and Linux. You can download it from http://linux.softpedia.com/get/System/Networking/PuTTY-347.shtml

Needed Mint 17.1 to talk to my Arduino, after a little chasing around, it turns out that your user must be part of the dialout group to use the tty. This should apply to Ubuntu as well. You can do so either by running the command:

sudo usermod -a -G dialout username

Administration → Users & Groups → Manage Groups

In which case you would go to the line for dialout , check the properties to ensure that username is ticked, if not username must be added.

This worked for me and by the look of lots of posts others have had the same problem.

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How to «usb to tty»?

persists information about devices you plug in, and you can modify this information so that it adds a specific ‘symlink’ in the directory for this device. I named my dongles ttyFTDI0 etc., and wrote the numbers on the dongles with a marker: Solution 3: This one-liner udev rule will give a fixed name (e.g. /dev/ttyUSB_A9YL5BJJ) based on serial number for any device with vendor/product ids as given. Put this into a udev rules file e.g. /etc/udev/rules.d/60-ftdi-serial-names.rules Question: I have an USB modem that I use on Ubuntu.

How to «usb to tty»?

I’m new to the C++ world but have strong knowledge in several languages (so i’m not THAT lost). I just received an usb missile launcher as a gift and wanted to control it via different platforms, including web. To do so, i was planning to use a «serial to socket» proxy i wrote in python (and then use socket after that. ). I found an opensource driver for my device, but it does not appear as a tty resource (with ls /dev/tty.*). That way, i’m not able to read/write into it with the pyserial library i use in my python script. My question is about finding tutorial/howto on creating such tty resources and «wire» them to usb devices.

on linux it is easy to access the usb ports directly using the libusb-dev package and tools. Of course commands etc. are vendor specific but there exist already libs for perl and python to control various usb missle launchers. E.g.:

Sorry that’s not a solution but hopefully a good starting point 😉

Ubuntu: How do I connect to TTY/COM (/dev/ttyUSB0)?, Ubuntu: How do I connect to TTY /COM (/dev/ttyUSB0)?Question: I am running Ubuntu for the first time by booting from a USB drive. Now I haveplugged in …

Ubuntu: How do I connect to TTY/COM (/dev/ttyUSB0)?

Ubuntu: How do I connect to TTY /COM (/dev/ttyUSB0)?Question: I am running Ubuntu for the first time by booting from a USB drive. Now I haveplugged in …

How to match a ttyUSBX device to a usb serial device

option driver correctly matched USB ID and loads driver for this device. For example

# lsusb Bus 001 Device 002: ID 19d2:0031 ONDA Communication S.p.A. ZTE MF636 Bus 001 Device 003: ID 12d1:14ac Huawei Technologies Co., Ltd. 

It also creates ttyUSBX devices for managing the hardware

crw-rw---- 1 root uucp 188, 0 Jul 4 13:48 /dev/ttyUSB0 crw-rw---- 1 root uucp 188, 1 Jul 4 13:49 /dev/ttyUSB1 crw-rw---- 1 root uucp 188, 2 Jul 4 13:35 /dev/ttyUSB2 crw-rw---- 1 root uucp 188, 3 Jul 4 13:37 /dev/ttyUSB3 crw-rw---- 1 root uucp 188, 4 Jul 4 13:37 /dev/ttyUSB4 crw-rw---- 1 root uucp 188, 5 Jul 4 13:37 /dev/ttyUSB5 crw-rw---- 1 root uucp 188, 6 Jul 4 13:37 /dev/ttyUSB6 crw-rw---- 1 root uucp 188, 7 Jul 4 13:37 /dev/ttyUSB7 

However, I have more then one usb serial devices and I want to know which ttyUSB is for which USBID. Ex. /dev/ttyUSB1 -> 19d2:0031

Do you know any point where I can get this information?

Have a look at the sysfs filesystem. An example for my USB serial:

$ lsusb Bus 003 Device 016: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port $ ls -l /sys/bus/usb-serial/devices lrwxrwxrwx 1 root root 0 Jul 4 17:37 ttyUSB0 -> ../../../devices/pci0000:00/0000:00:1c.0/0000:02:00.0/usb3/3-1/3-1:1.0/ttyUSB0 $ $ grep PRODUCT= /sys/bus/usb-serial/devices/ttyUSB0/../uevent PRODUCT=67b/2303/300 

As you can see, ttyUSB0 maps to 067b:2303 on my computer. An other locations worth exploring are /sys/class/tty/ . Pay attention to symlinks.

You can try to see if your device(s) are registered under /dev/serial/by-id/

These names should be consistent and will point (symlink) to the correct ttyUSBx

Write this to /etc/udev/rules.d/50-usb.rules

SUBSYSTEM=="tty", ATTRS=="19d2", ATTRS=="0031", SYMLINK+="ONDA" SUBSYSTEM=="tty", ATTRS=="12d1", ATTRS=="14ac", SYMLINK+="HUAWEI" 

Now you can use /dev/ONDA to get to your ONDA device.

If you want non-root users to be able to use these, then add

I would use udev and write some rules which create symlinks for the devices.

To get enough information to distinguish the devices try something like this for all devices:

$ udevadm info --query all --name /dev/ttyUSB0 --attribute-walk 

Find which TTY device connected over USB, The adb ppp command to switch back to the USB cable instead of tcp/ip says it needs the tty as a parameter. I have googled for this and found lots of references to solutions that don’t work. A lot of those point to ttyUSB0, which doesn’t seem to exist on my system. I am running Ubuntu Desktop 12.04. How …

How to find out which USB-RS232 device is on which tty?

I have two different USB devices based on the same USB-RS232 chips. When I plug those in the USB they are mounted to /dev/ttyusb0. 3

My problem is how, inside a script, I can find out which one is on what tty?

Using lsusb I can differentiate them:

$> lsusb | grep 0403:f850 Bus 004 Device 002: ID 0403:f850 Future Technology Devices International, Ltd $> lsusb | grep 0403:6001 Bus 004 Device 003: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC 

And using dmesg I can tell where they were mounted:

$> dmesg | grep 'FTDI USB Serial Device converter now attached' [36051.393350] usb 4-2: FTDI USB Serial Device converter now attached to ttyUSB1 [36061.823513] usb 4-1: FTDI USB Serial Device converter now attached to ttyUSB0 

But «usb 4-1» does not seem to correspond to «Bus 004 Device 002».

Can I assume that «Bus 004 Device 001» will always be an «USB root hub» and thus dmesg will count from 1 onwards and lsusb from 2 onwards?

Or do you have another suggestion on how to correlate device ID to mount point (inside a script)?

Find more info using sysfs:

$ ls /sys/bus/usb-serial/devices/ -ltrah lrwxrwxrwx 1 root root 0 2012-02-07 22:17 ttyUSB0 -> ../../../devices/pci0000:00/0000:00:0f.4/usb2/2-2/2-2:1.0/ttyUSB0 $ ls -ltrad /sys//devices/pci0000:00/0000:00:0f.4/usb2/2-2/2-2:1.0/ttyUSB0 drwxr-xr-x 4 root root 0 2012-02-07 22:17 /sys//devices/pci0000:00/0000:00:0f.4/usb2/2-2/2-2:1.0/ttyUSB0 $ ls -ltrad /dev/ttyUSB0 crw-rw---- 1 root dialout 188, 0 2012-02-01 00:17 /dev/ttyUSB0 

Of course, the linked devices/. node contains a lot of information

Adding information based on the OP’s comment:

The device number keeps growing if devices are removed/inserted. lsusb -t can be used to correlate the device numbers with usb bus/port.

Then, ‘lsusb -d devID’ can determine what device is on which port. Finally ‘ls /sys/bus/usb-serial/devices/ -ltrah’ will list (by bus/port) where it was mounted.

Not very convenient, but it ‘ works ‘

You can use udev to assign a stable symbolic link to each FTDI dongle. Use device and vendor to match the type, and then the serial number for the specific device. Then use the symbolic link in the script.

I named my dongles ttyFTDI0 etc., and wrote the numbers on the dongles with a marker:

$ cat /etc/udev/ftdi.rules SUBSYSTEMS=="usb", KERNEL=="ttyUSB*", ATTRS=="0403", ATTRS=="6001", ATTRS=="FTDEN97D", SYMLINK+="ttyFTDI0" SUBSYSTEMS=="usb", KERNEL=="ttyUSB*", ATTRS=="0403", ATTRS=="6001", ATTRS=="A600b30P", SYMLINK+="ttyFTDI1" SUBSYSTEMS=="usb", KERNEL=="ttyUSB*", ATTRS=="0403", ATTRS=="6001", ATTRS=="A600bexU", SYMLINK+="ttyFTDI2" SUBSYSTEMS=="usb", KERNEL=="ttyUSB*", ATTRS=="0403", ATTRS=="6001", ATTRS=="FTFMSA54", SYMLINK+="ttyFTDI3" SUBSYSTEMS=="usb", KERNEL=="ttyUSB*", ATTRS=="0403", ATTRS=="6001", ATTRS=="FTFMUW4A", SYMLINK+="ttyFTDI4"

This one-liner udev rule will give a fixed name (e.g. /dev/ttyUSB_A9YL5BJJ) based on serial number for any device with vendor/product ids as given.

Put this into a udev rules file e.g. /etc/udev/rules.d/60-ftdi-serial-names.rules

SUBSYSTEM=="tty", ATTRS=="0403", ATTRS=="6001", ENV=="?*", SYMLINK+="ttyUSB_%E" 

How to find tty of USB modem on raspberry pi?, I have tried to connect the modem with cu tool: sudo cu -l sda sudo cu -l sg0. but both returns: cu: open (/dev/sg0): Permission denied cu: sg0: Line in use. So I tried also use minicom and configure serial communication to /dev/sg0 or /dev/sda but it does not work either. So I think I need to find right tty device used …

Linux: how to force a USB device to use the same ttyUSB number

I have an USB modem that I use on Ubuntu. I have also a program which communicate with this device using its ttyUSBxx number.

My problem is that every time I unplug/plug the device again, or when I reboot my PC, the device gets a new ttyUSB number, for example: ttyUSB0 or ttyUSB1 .

How can I force this device to always use the same number (say: ttyUSB0 )?

udev is Linux’s dynamic device manager. udev persists information about devices you plug in, and you can modify this information so that it adds a specific ‘symlink’ in the directory for this device.

Now, your usb modem’s definition should be inside the folder /etc/udev/rules.d/ , and the filename will be something like 50-udev.rules . The file contains one line per device, (you can use a number of tools to help identify the correct line. See below link on using udevinfo )

Now, you can edit the relevant line, or even better, create another file and copy the relevant line into it. The filename should start with a lower number (e.g. 49-my-modem.rules ), so that it gets loaded first. You need to add the following to the end of the line:

Now, your device should come up as /dev/ttyUSBmodem (aswell as the dynamically assinged /dev/ttyUSB3)

For more help with identifying the correct line and the whole process, see here: http://noctis.de/archives/16-HowTo-fixed-name-for-a-udev-device.html

Usb — How to read/write to tty* device?, The TTYs that back your terminal will be owned by you, but another user’s TTY won’t, and TTYs for USB devices may or may not be, depending on your configuration. You can change the permissions in the same way as always. As far as writing a program to work with it goes, you don’t need to do much special.

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