- I was using the suggestions in this post to write to a serial port, then using the info from another post to read from the port, with mixed results. I found that using screen is an 'easier' solution, since it opens a terminal session directly with that port.
- Some motherboards come with a serial port with no cable or external serial DB connector. Someone may build a PC from this and decide not to use this serial port. There may be a 'serial' connector and label on the motherboard but no ribbon cable connects to its pins. To use this port you must get a ribbon cable and connector.
Ubuntu Serial Port Tool
Active1 month ago
Is there a way to connect to a serial terminal just as you would do with SSH? There must be a simpler way than tools such as Minicom, like this
I know I can
cat
the output from /dev/ttyS0
but only one way communication is possible that way, from the port to the console. And echo
out to the port is just the same but the other way around, to the port. How can I realize two way communication with a serial port the simplest possible way on Unix/Linux?
ihatetoregister
ihatetoregisterUbuntu 12.04LTS and later is default equipped with the Silabs drivers! No installation of drivers is necessary. The only thing necessary is to check whether the Ubuntu machine can communicate over USB with the attached Xilinx development board. To do this: Connect the PC via an USB cable to the USB UART port of the Xilinx development board. Minicom is a text-based serial port communications program. It is used to talk to external RS-232 devices such as mobile phones, routers, and serial console ports. Install the program with: sudo apt-get install minicom. Alternatively, you can get Minicom via the Synaptic Package Manager. Using the program. Setserial - get/set Linux serial port information SYNOPSIS setserial -abqvVWz device parameter1 arg. Setserial-g -abGv device1. DESCRIPTION setserial is a program designed to set and/or report the configuration information associated with a serial port. This information includes what I/O port and IRQ a particular serial port is.
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16 Answers
I find
Shawn J. GoffShawn J. Goffscreen
the most useful program for serial communication since I use it for other things anyway. It's usually just screen /dev/ttyS0 <speed>
, although the default settings may be different for your device. It also allows you to pipe anything into the session by entering command mode and doing exec !! <run some program that generates output>
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Background
The main reason why you need any program like
minicom
to communicate over a serial port is that the port needs to be set up prior to initiating a connection. If it weren't set up appropriately, the cat
and echo
commands would not do for you what you might have expected. Notice that once you run a program like minicom
, the port is left with the settings that minicom
used. You can query the communication settings using the stty
program like this:If you have done it right; after booting the computer and before running any other program like
minicom,
the communication settings will be at their default settings. These are probably different than what you will need to make your connection. In this situation, sending the commands cat
or echo
to the port will either produce garbage or not work at all. Run
stty
again after using minicom
, and you'll notice the settings are set to what the program was using.Minimal serial communication
Basically, two things are needed to have two-way communication through a serial port: 1) configuring the serial port, and 2) opening the pseudo-tty read-write.
The most basic program that I know that does this is
rozcietrzewiaczrozcietrzewiaczpicocom
. You can also use a tool like setserial
to set up the port and then interact with it directly from the shell.30.8k44 gold badges7979 silver badges9696 bronze badges
If UUCP is installed on the system, you may use the command cu, e.g.
ktfktf
I found a way using a shell script here that put
heemaylcat
as a background process and a while loop that read the user input and echo
it out to the port. I modified it to be more general and it fitted my purpose perfectly. 38.7k44 gold badges8484 silver badges112112 bronze badges
ihatetoregisterihatetoregister1,43533 gold badges1515 silver badges1515 bronze badges
Try http://tio.github.io
'tio' is a simple TTY terminal application which features a straightforward commandline interface to easily connect to TTY devices for basic input/output.
Typical use is without options. For example:
Which corresponds to the commonly used options:
It comes with full shell auto completion support for all options.
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MartinMartin
This script is based on another answer, but sends everything over the serial port (except Ctrl+Q), not just single commands followed by Enter. This enables you to use Ctrl+C or Ctrl+Z on the remote host, and to use interactive 'GUI' programs like aptitude or alsamixer. Keil license key generator. It can be quit by pressing Ctrl+Q.
Community♦
FritzFritz
BTW, the putty package (which does run on Linux) does include serial support.
mdpcmdpc5,27822 gold badges1919 silver badges3838 bronze badges
Putty works well on Linux and offers some convenience, especially for serial communications. It has one drawback I haven't been able to directly solve: no copy-paste from the Putty window itself. The windows version has a lovely auto-copy to clipboard on highlight, right-click to paste behaviour (and there are excellent plugins for both chrome and firefox to enable the same behavior), but on Linux, no copy love AFAIK.
If the lack of copy is a problem (it is for me) then turn on logging in putty and open a standard terminal window and
# tail -f putty.log
and bidirectional text is available for standard copypasta action.gesselgessel
Another issue that can occur is that your user account may need to set to the 'dialout' group to access the serial port.
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dfowler7437dfowler7437
It depends on what you want to do. Do you want to run a shell or applicaiton interactively from the terminal, connect out to another computer over the serial line, automate communication with a device over a serial port?
If you want bidirectional communication then I presume you want something interactive with a human on the terminal. You can configure the system to allow logins from a terminal over a serial port by seting up a getty(1) session on the serial port - getty is the tool for setting up a terminal and allowing logins onto it. Put an entry in your inittab(5) file to run it on the appropriate serial port on a
respawn
basis.If you want to connect to a device and initiate automated two way conversations then you could see if expect will get you what you want. Use stty(1) to configure the port to the right parity, baud rate and other relevant settings.
If you want to communicate interactively with another computer over the serial port then you will need terminal emulation software. This does quite a lot - it sets up the port, interprets ANSI or other terminal command sequences (ANSI was far from being the only standard supported by serial terminals). Many terminal emulators also support file transfer protocols such as kermit or zmodem.
The ins and outs of serial communications and terminal I/O are fairly complex; you can read more than you ever wanted to know on the subject in the serial howto.
ConcernedOfTunbridgeWellsConcernedOfTunbridgeWells
As mentioned before you can try picocom. The latest release (2.0) can also be used (safely) to set-up a 'terminal server' since it no longer permits shell command injection. See:
Nick PatavalisNick Patavalis
You might want to take a look at
Pro: doesn't have obvious security problems like minicom or picocom (if you don't have a problem giving the users shell access, no problem, but you most likely do have one if you want to set up a terminal server..)
PeterPeter
You need to be sure to have the correct read write permits on the device, you could see it with:
I rely on the script you found and made some modifications.
For the development systems I've used by now, they used to need:
- None parity and
- One stop bit
Those values are the default ones in the script.
So in order to connect, you can use it as simple as follows:
Example:
Script:
P.S.: You need to know which kind of line feed is using your receiver system since this will determine how you'll need to send the commands in my case I needed a Windows like LF, means that I need to send
ASCII values for:
- LF : 0Ah, line feed 'n'
- CR : 0Dh, carrige return 'r'
- BS : 08h, back space '<-'
Rafael KarosuoRafael Karosuo
As it is not mentioned here already, I'd also mention
socat
- more info in https://stackoverflow.com/questions/2899180/how-can-i-use-com-and-usb-ports-within-cygwin :or
(though, I've had the problem of stopping it once it starts running, under MSYS2 on Windows)
sdbbssdbbs
Ubuntu Serial Port App
I wonder why nobody mentioned ser2net.
Example
/etc/ser2net.conf
:Linux Serial Tools
You can connect to serial port as easy as:
Or remotely:
Or even set up port forwarding on your router and expose it to Internet, so that you could connect to it from anywhere (let's skip security issues, I'm talking about flexibility).
Andrejs CainikovsAndrejs Cainikovs
Another easy option is to access the machine over ssh with the
-X
flag and run a program such as putty or gtkterm.So:
It should launch the graphical interface on your client PC and from there you can access the serial port as if you would be in the host.
Disclaimer: Only tried this with ubuntu machines. I'm guessing that it won't work with machines without graphic interfaces.
From the ssh manual:
-X
Enables X11 forwarding. This can also be specified on a per-host basis in a configuration file. X11 forwarding should be enabled with caution. Users with the ability to bypass file permissions on the remote host (for the user's X authorization database) can access the local X11 display through the forwarded connection. An attacker may then be able to perform activities such as keystroke monitoring. For this reason, X11 forwarding is subjected to X11 SECURITY extension restrictions by default. Please refer to the ssh -Y option and the ForwardX11Trusted directive in ssh_config(5) for more information.
-Y
Enables trusted X11 forwarding. Trusted X11 forwardings are not subjected to the X11 SECURITY extension controls.
So use
-Y
if security is an issue.GrifoGrifo