Why the "lspci" command does not list the serial ports? I have enabled two serial ports in VirtualBox, and then typed the `lspci` command in Ubuntu, and this is the result: ![enter image description here]( The serial ports are not listed, is it because the serial ports are not part of the PCI bus?

> is it because the serial ports are not part of the PCI bus?

Yes. Traditional PC serial ports on x86 hardware interface with applications via old-style ISA I/O ports and interrupts.

Keep in mind that RS-232 data rates are down in the kHz range in the vast majority of cases. PCI holds no advantage for RS-232.

Add-on PCI serial port cards may appear in `lspci` output, but that's more about available slots than the appropriateness of PCI to RS-232.