Is it possible to connect to a COM port without using RS232?

Question

linux

Now more specifically.
Is it possible to implement some kind of COM port emulation via a USB>USB cable in Ubuntu. I was interested in the possibility of logging into the console in case the network daemon closes or something else happens, which makes it impossible to connect to ssh.
There are no COM ports on the computer and on the home server.
I understand that the question may be incompetent, but it's very interesting.

Answer 1

Isn't it easier to buy a usb-comport? price <100r ru.aliexpress.com/w/wholesale-usb-rs232.html?spm=2
...

Answer 2

Exactly how /dev/ttyUSB0 or ​​/dev/ttyACM0 (and this is COM in your terminology) Linux perceives the whole set of USB wireless modems (3G, 4G, GPRS, EVDO, etc.) ... as well as some other USB devices.
This is provided by the (USB as serial) Linux kernel module usbser.
But to implement your idea for your specific application - it will have to sweat ;-) Have a quick
look at Installing and configuring USB modems - you might see useful details there.
PS And if it's already bad, then today there are a lot of COM-> USB converters on the market at a penny cost.

Answer 3

As already mentioned, we buy two USB <-> UART adapters. We connect one to our computer, the second to a laptop / another computer. We connect them Rx / Tx crosswise.
On the server, we configure the launch of the terminal on the adapter (if there is more than one adapter, you will also have to add the udev rule for identification), for which we write the line in /etc/inittab
All. Run (init term) and connect from laptop/other computer using com: utility
or screen session.