VBox or OS COM Port Limitations

[superhumanben]

I've hit a snag. I'm using a COMTROL octo card to product 8 COM ports on a single server. Setting the card to start at COM2-9, everything goes fine. As soon as I go above COM10, I cannot get a virtual to start. I'm getting the error "Failed to open host device 'COM20' (VERR_FILE_NOT_FOUND) .

Host PC running Windows 2003 R2 SP2, guests running Windows XP SP3.

I'll double check the BIOS and see if there's anything limiting this but at this point I'm at a complete loss. I'm not sure if this is a limitation in VirtualBox to not accept anything over COM10 or if it's simply something I'm missing.

[Perryg]

You should read Chapter 3.7.6. Serial ports
<snip>
In either case, you can configure up to two virtual serial ports simultaneously. For each such device, you will need to determine....
<snip>

[superhumanben]

I have read that chapter and it says nothing about my issue.

What I'm trying to do. Make 4 virtual sessions on 1 system, each with 2 com ports. If I try to use COM10 and above, Virtual box does not work.

I've changed around the configuration 4 different times and can get them all to work if I stay under 10. The major problem with this is we're using this 8 port as a proof of concept in hopes to go to a 32 port solution. If I can't get over 8, then this project is dead in the water.