12.04serial port
I am unable to access the serial port on my PC with Ubuntu 12.04.
The command:
dmesg | grep ttyS
Outputs:
[ 0.590705] 00:08: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
I think serial port is not getting detected.
Can anyone please help me in solving the problem?
Setting up a serial port for VirtualBox is not easy, mainly because of many options on how to transfer data from the host to the guest. For transferring data from/to an attached device (here a modem) the following settings should work:
Of course you will have to adopt setting for your device on the host (that would be /dev/ttyS2 in your case).
If using an IRQ greater than 15 for the host you will have to enable I/O APCI as shown here:
After a setup depicted in the example here your Windows guest will see a virtual type 16450 serial port on COM1 using IRQ4 and I/O Port 0x3F8. Data will be transferred from and to host device /dev/ttyS20.
You may suffer from a bug in earlier versions of virtual box:
https://www.virtualbox.org/ticket/7411
This issue was fixed from Virtual Box release 4.1.0.
You may succed by simply upgrading to the most recent version (at present 4.1.8).
Best Answer
The line above tell us that the kernel detected a 16550 UART chip in your PC, which provides a serial port (ttyS0), and there's some resources allocated to it (0x3f8 I/O address, IRQ 4).
The default permissions for serial devices are the following:
So, if you are a member of the
dialoutgroup, you'll be able to access (read from/write to) the serial port devices. Add yourself to thedialoutgroup by running:Or:
Then log out and log in again. Now you should have access to the serial port. Of course, you must also input the correct settings (speed, data bits, parity, stop bits, flow control) in the program you're using to access the device.