How to Connect to a Terminal to a Serial-To-Usb Device on Ubuntu 10.10 (Maverick Meerkat)

How do I connect to a terminal to a serial-to-USB device on Ubuntu 10.10 (Maverick Meerkat)?

First check with dmesg | grep tty if system recognize your adapter.
Then try to run minicom with sudo minicom -s, go to "Serial port setup" and change the first line to /dev/ttyUSB0.

Don't forget to save config as default with "Save setup as dfl". It works for me on Ubuntu 11.04 on VirtualBox.

Serial Input in Ubuntu, Usb to serial converter (Pl2303 - Prolific) not working in ubuntu 18.04

Need to set the permissions for /dev/ttyUSB0.
If user dialout is cumbersome, then we have to grant universal permissions to /dev/ttyUSB0.
Command is "sudo chmod 666 /dev/ttyUSB0"

Why does read not terminate for my USB device?

I found the Answer myself: the ICANON bit in the termios struct, c_lflag field musst be cleared and the VMIN field in the c_cc array should be set to 1.

Further explanations are found here:

https://www.gnu.org/software/libc/manual/html_node/Local-Modes.html#Local-Modes
https://www.gnu.org/software/libc/manual/html_node/Mode-Data-Types.html

(be carefull, some parts of this documentary are a little bit outdated, for example the CCTS_OFLOW Flag does not exist on Raspbian-Buster)

how to communicate with devices via a USB-to-RS232 wire in Linux?

Your USB-to-RS232 is probably using an FTDI chip. The idea in Linux is that any drivers added to the kernel can by accessed by manipulating an entry in the /dev filesystem.

The very first thing you need to know when working with Linux (or any UNIX variant) is that everything is a file. So unlike Windows (where a manufacturer creates a dll and tells you which functions to call) in Linux you use standard file system functions (note to the purists: I am leaving out ioctl for simplicity reasons)

So look in the dev directory and see what entries appear when you plug your "wire" in and what disappears when you take it out. As roderigo mentioned, the device file is most probably called ttyUSB0, but ttyS0 is not impossible.

In your program you then open this "file": fd = open("/dev/ttyUSB0", O_RDWR)
You can use the functions write and read to send and receive characters from your com port. When you're finished close the port with close(fd)

To set your line parameters search either the minicom source or the Linux documentation for the termios structure.

Get a hold of the book "Linux Programming Unleashed" by Kurt Wall, et al. I think it is a must have for anyone writing C code for applications running on Linux.

Good luck.

Reading from usb as a comport

You should read some basic USB information.

The difference you've noticed is because USB supports something called "device classes", that basically control how the computer (the host) views the device.

One such class is "USB communications device" which often becomes a virtual COM port, for instance.

Another is the very commonly seen "USB mass storage device" which is what e.g. flash drives use.

A third is the one you mention for mouses and keyboards, which is called "USB human interface device".

Which class a particular device uses is communicated when it's first connected on the bus, so that the host can load the proper driver. You cannot magically force a device to switch classes, the class is typically a "hard" (non-modifiable) part of the device's implementation, chosen by the designers of the device.