Serial Pass-through Communication Errors


Well-Known Member
Nov 18, 2017
Hey everyone. I have a situation where I have setup Proxmox on a HP Elite 8200 and am having a few odd issues in relation to native serial passthrough. I have an old industrial controller that was running on an old XP that is now being retired, and I decided to setup Windows 10 in a VM and pass through the serial port. Everything works fine, except I get constant connection problems in the VM. It will work for a few moments while, but then I will get an error message, seemingly randomly, that there was a communication problem.

To rule out the hardware or OS as problem, I cloned the VM to another HP Elite 8200 and the software works perfectly via COM there. Same cable, and I'm pretty sure the 1st HP Elite 8200 has no hardware issues either since I used to use it for interfacing with old managed switches a few years back.

Any ideas on how I could resolve this issue? I am running Proxmox 5.3.2 at the moment. Any suggestions would be greatly appreciated!


The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get yours easily in our online shop.

Buy now!