Jump to content

Setup External Serial Modem on Ubuntu Server


Recommended Posts

IDENTIFY your serial ports on server

$ dmesg | grep tty
[    0.000000] console enabled
[    0.534814] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[    0.632375] serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
[    0.992562] 00:06: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[    1.013084] 00:07: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A


INSTALL the ability to set your serial port

$ sudo apt-get install setserial


CONFIGURE serial port using set serial

$ sudo setserial -g /dev/ttyS0
/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4


INSTALL minicom so you have a command line dialing software

$ sudo apt-get install minicom


SETUP minicom for the correct serial port (ttyS0 in this example)

$ sudo minicom -s


RUN the command line software minicom

$ minicom -c on


GROUP membership. By default users don't have access to the serial ports so you have to give them access. First check which group do you need to be in to access serial port ttyS0 for example.

$ sudo ls -la /dev | grep ttyS0
crw-rw----  1 root dialout   4,  64 May  2 11:05


Now you see the user needs to be a member of the group dialout, check your the id's current group membership

$ id dhosanguid=2009(dhosang) gid=2009(dhosang)





$ groups dhosangdhosang : dhosang adm cdrom sudo www-data staff
users crontab syslog ssh sambashare admin mysql kvm libvirtd shared



$ cat /etc/group | grep dialoutdialout:x:20:admin


So the user (dhosang) isn't a member of the required group (dialout) so let's add the group to the user

$ sudo adduser dhosang dialout





Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...