Saturday, May 23, 2015

Serial Console setup

For many years I didn't bother setting up a serial console because I for some reason thought that it's a troublesome process, esp. from the hardware side of things, because modern motherboards don't have serial ports on their backside, serial port controllers would probably need some driver that might be not available for FreeBSD etc. That's what I thought. Actually, everything is much simpler.

A couple of weeks ago I've ended up in a situation when I really needed to know what's going on and it was not possible without a serial console, so I decided to finally try to setup it.

The motherboards I have in my computers are:

  • Gigabyte H61M-S2V-B3
  • Asus B85M-E

As I have mentioned, they don't have COM ports on the rear panel. However, it turned out that they both have a serial module connector on the board itself. I don't know how common is that for desktop motherboards, but considering that I didn't pay attention to that when buying them and both appeared to have them, I think it's quite common.

Unfortunately, I wasn't able to find these COM modules, so I just decided to buy a COM controller with 2 COM modules on-board and put them off without using the actual controller.

I put them off, plugged to my motherboards and connected via null modem cable. Things started working as expected!

On the test server I have this configuration in /boot/loader.conf:

# console

To connect to it from the other host I use:

screen /dev/cuau0 115200

Budget of this operation is ~15$ for the COM controller and ~4$ for the null-modem cable in a radio shop.

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