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Connect virtual serial port to physical serial port

Posted: 27. Apr 2016, 16:50
by stagnette
Hello everyone,

I have installed VirtualBox 5.0.18 with Windows XP SP3 Pro (hosted) on an Ubuntu 14.04 (host), and I have to connect a device using a VGA port but it is not recognised by the virtual machine. The user's manual says
You can connect the virtual serial port to a physical serial port on your host. (On a Windows host, this will be a name like COM1; on Linux or Solaris hosts, it will be a device node like /dev/ttyS0). VirtualBox will then simply redirect all data received from and sent to the virtual serial port to the physical device.
[3.9] but I have no idea of what the device node is...

May someone help me? :)
Thanks a lot

Lucas

PS : sorry for my English, I'm French

Re: Connect virtual serial port to physical serial port

Posted: 27. Apr 2016, 17:18
by Perryg
Lots of difference between a serial port and a VGA port. So it probably will not work. Perhaps if you explained a bit more someone could tell you a better way.

Re: Connect virtual serial port to physical serial port

Posted: 27. Apr 2016, 17:45
by stagnette
Well the device I need to plug in is an old one, and the thing I try to do is doing a back-up of it. And to do so, I have to use a special app made in 2000, which can only interact with the device via a VGA cable (there is no USB port). The application is well installed in Windows XP but is unable to detect the device, and vice-versa.

By the way, none of the peripheral devices works with the virtual machine (USB port, CD...).

I don't know if it helps but the computer I use is a Dell Optiplex 745.

Thanks again!

Re: Connect virtual serial port to physical serial port

Posted: 27. Apr 2016, 17:48
by Perryg
First post the guests log file ( as an attachment ). Right click on the guest in the Main Manager then click show log. Save and post as an attachment. Compress if it is too large to post.

Re: Connect virtual serial port to physical serial port

Posted: 27. Apr 2016, 18:05
by stagnette
Here it is :)

Re: Connect virtual serial port to physical serial port

Posted: 27. Apr 2016, 18:10
by mpack
Are you sure you need to use the VGA port? The VGA port is 15 pin D connector, a PC RS232 connector is a 9 pin D connector. Their appearance may be similar if you don't count the pins, but their functionality is totally different.

Nobody has ever used a VGA port on a PC for communications - the signals are analog, and parallel, and the cable is not bidirectional nor is actually connected to the PC - it connects to the graphics card (or chipset).

Re: Connect virtual serial port to physical serial port

Posted: 27. Apr 2016, 18:17
by stagnette
Mmh I think you're right, it's a RS232 port! I'm sorry for the confusion...

Re: Connect virtual serial port to physical serial port

Posted: 27. Apr 2016, 18:49
by Perryg
As for your second post in this topic where you say that even the USB does not work, that is easily explainable. You have not installed the Extension Pack yet. You need to also make sure that you add your user name to the vboxusers group on the host followed by a reboot of the host.

As for the rest of this concerning a serial port I will leave you in Don's competent hands. I don't have any on my machine/s and it would be fruitless for me to try to figure out your real issue.

Re: Connect virtual serial port to physical serial port

Posted: 28. Apr 2016, 15:38
by stagnette
Thanks! Now I've installed the Extension Pack but I think I didn't manage to find how to add my user name to the vboxusers group writing "sudo usermod -a -G vboxusers <username>" in the terminal but nothing changed since... But it's not the main problem, as the only reason I installed this virtual machine is to make back-ups via the RS323 port (which still doesn't communicate)

Re: Connect virtual serial port to physical serial port

Posted: 28. Apr 2016, 15:43
by Perryg
Assuming you actually replaced <username> with your real user name, permissions do not become effective until the host is logged out or rebooted. You can type id in the terminal and see if it is enabled.

Re: Connect virtual serial port to physical serial port

Posted: 28. Apr 2016, 16:46
by stagnette
Yes of course, I replaced <username> by "manivelles", then I've been asked to write my password, which I did and then I rebooted the host machine.
When I type "id", it returns
uid=1000(manivelles) gid=1000(manivelles) groupes=1000(manivelles),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),108(lpadmin),124(sambashare),125(vboxusers)
manivelles@Cycles:~$

Re: Connect virtual serial port to physical serial port

Posted: 28. Apr 2016, 16:52
by Perryg
Very well. Since as you said this would be redundant if you can not get the serial port to work I will wait until you decide to proceed with the USB portion until you decide you really want it.

Re: Connect virtual serial port to physical serial port

Posted: 28. Apr 2016, 17:01
by stagnette
I'm sorry, I don't understand what you wait for me to do. In order to do the back-ups of the peripheral device, I have no other choice than to plug it in the serial port anyway...

Re: Connect virtual serial port to physical serial port

Posted: 28. Apr 2016, 17:36
by stagnette
Or maybe I should try to install an older version of Virtualbox, as I read on this very forum that USB peripheral devices were no longer recognised (so it may be the same with serial ports)?

Re: Connect virtual serial port to physical serial port

Posted: 28. Apr 2016, 17:38
by Perryg
You said the only reason for this was to use a serial port on a guest to do backups. I can not help you with that because I don't have any machines that actually have a serial port. Don or someone else that do will need to help with that.

If you have changed you mind and want the USB to work even if the serial port will not then let me know and we can proceed. Other than that it would be a waste of time to go through all of this and then you decide to not use virtualization.