https://www.howtoforge.com/how-to-set-up-a-serial-port-between-two-virtual-machines-in-virtualbox
I needed to test serial communication between two VirtualBox guest machines on Linux. This tutorial describes what I did to set up a serial port between two virtual machines running on VirtualBox.
- My host operating system was Ubuntu 10.10
- My guest operating systems were Microsoft Windows XP and Debian Lenny.
On the host machine you don't need to install or configure anything.
On guest virtual machines you need to configure serial port settings.
First Guest VM Serial Port Settings - Debian
Figure 1. - First Guest VM Serial Port Settings
Enable Serial Port check box: checked (enabled)
Port Number: COM1
Port Mode: Host Pipe
Create Pipe check box: checked (enabled)
Port/File Path: /tmp/vboxS0
Second Guest VM Serial Port Settings - Microsoft Windows XP
Figure 2. - Second VM Serial Port Settings
Enable Serial Port check box: checked (enabled)
Port Number: COM1
Port Mode: Host Pipe
Create Pipe checking box: unchecked (disabled)
Port/File Path: /tmp/vboxS0