Guruplug serial connection



If you cannot connect to guruplug for some reason via lan interface, for example sshd stopped running or just firewalled yourself out of it, you can connect to it using serial connection.

When making order guruplug from original site , by adding few more bucks you can get development kit.

For serial connection you need only smaller connector, the bigger one is used for jtag connection, which is used if you brick the device.

For connection in linux you can use small program called minicom.
You can find it in your distro repository.

Starting install:

$ sudo apt-get install minicom

Now connect your devkit to your computer using mini usb cable.
Enter command


You should get output something like this:

[13997.188105] usb 3-1: new full speed USB device number 3 using uhci_hcd
[13997.408410] usb 3-1: Ignoring serial port reserved for JTAG
[13997.413595] ftdi_sio 3-1:1.1: FTDI USB Serial Device converter detected
[13997.413792] usb 3-1: Detected FT2232C
[13997.413807] usb 3-1: Number of endpoints 2
[13997.413820] usb 3-1: Endpoint 1 MaxPacketSize 64
[13997.413833] usb 3-1: Endpoint 2 MaxPacketSize 64
[13997.413845] usb 3-1: Setting MaxPacketSize 64
[13997.416502] usb 3-1: FTDI USB Serial Device converter now attached to ttyUSB0

On last line you can see, that device is attached as “ttyUSB0”.
We’ll use it in minicom settings.

Lets start the minicom (-s stands for “setup”)

$ minicom -s

On open menu, choose “Serial port setup”
You’ll have something like this:

Press letter “A”, to change Serial device, and enter address of your devkit.
if you had ttyUSB0, then you should write /dev/ttyUSB0 and press enter.
Then press letter “E” to change “Bps/Par/Bits” settings.
In opened window press letters “E” (speed 115200) and “Q” (Parity “none”, Data – 8, Stop bits – 1), then press enter.
By pressing letters “F” and “G” make sure that Flow control settings are both set to “off”.
If it’s all done, just press enter to get back to previous menu.
Press “Exit” (Do not press “Exit from minicom”!!! As it will exit from minicom program).
If you want to save it as default settings, you need to start minicom as root (“sudo minicom -s”).

Now minicom window should appear. Powerup guruplug to outlet, and you should get all output from it.

To quit from minicom program, you have to press
ctrl+A then Z and X


10 responses to “Guruplug serial connection”

  1. how to fix Error:
    minicom: can not open /dev/ttyUSB0: permission denied

    1. check if it really exist, also permissions with:
      ls -lah /dev/ttyUSB0

      if it’s only permission problem, it may require administrator privileges to open ttyUSB0, so try the same command with “sudo” in front of command, or just login as root.

  2. I’m trying sudo minicom -s, window show:
    Welcome to minicom 2.5

    OPTIONS: I18n
    Compiled on May 2 2011, 10:05:24
    Port /dev/ttyUSB0

    press CTRL-A Z for help on speccial key

    1. if You’ll make all settings like in screenshots, everything should be fine. I needed to reinstall guruplug, so I used these settings and it all worked.
      After making connection – turn on guruplug, all output should appear in that minicom console.

  3. I need to install a driver for GURU?

    1. no additional drivers needed. Minicom is only for making serial connection, that’s it.

  4. Thanks!
    In case on, you use Ubuntu (I se command install apt-get..)
    but in Quick start guide for GuruPlug Server.pdf use Fedora
    so, it work fine on Ubuntu?
    In GuruPlug Server.pdf in which mention install: Ftdi_sio.ko (FTDI device driver module for Linux), must be install it?

    1. Hmm, as i did quick peek to google, seems yes, on some Distros ftdi.sio.ko might be needed. As it’s USB to Serial driver of some kind.
      Before that driver You didn’t even see /dev/ttyUSB0 device?
      What dmesg says when You connect that serial interface?

      On ubuntu(tested when I was writing this post) and on debian (currently I’m on debian, and I recently wanted to reinstall guruplug) serial interface works without any additional packages.
      Only minicom (soft for comunicating via serial interface) is needed and that’s it. Also, other software might be used (minicom is the most popular and easy), but serial connection settings should remain the same.

  5. hi nsc
    I want configure Ip Guru by command:
    Marvell>> setenv ipaddr
    Marvell>> setenv serverip
    after must be command? :

    1. no, reset would reset that device.
      Just fill commands that You wanted to use.
      “setenv serverip” it’s the IP address of server that you are going to get packets from, so don’t forget to set this IP on it.

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