Intel Motherboards - BIOS not reachable when using KVM Switch

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BIOS not reachable when using KVM Switch

Printed From: ASRock.com
Category: Technical Support
Forum Name: Intel Motherboards
Forum Description: Question about ASRock Intel Motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=9016
Printed Date: 13 Aug 2025 at 2:06am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com

Topic: BIOS not reachable when using KVM Switch

Posted By: Maverick3
Subject: BIOS not reachable when using KVM Switch
Date Posted: 25 Jun 2018 at 8:20pm

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Hi all,

I'm using an Aten CS1784A KVM switch as I have to switch my Keaboard/Mouse and Display between different computers.
The Mouse and the Keyboard are connected to the KVM and from there one USB connection is made to the Computer. The cable coming from the KVM is plugged into a USB2.0 Port. The Board is a Z270 Extreme 4 with BIOS Ver. 2.70.

When I want to go into the BIOS or want to select a different boot device, the keystrokes of the Keyboard are not recognized by the board (in the POST phase). When the system has booted Windows 10 then everythings works like it should.

When the keyboard is directly connected to the USB port of the board (without the KVM switch between) then I can get into BIOS and the boot device screen.

With the Aten support I could identify that the problem seems to be. that the board is not recognizing keystrokes in the POST phase when the keyboard is connected via an USB hub to the Board. (Connect a USB hub to a USB 2.0 POrt of the board and plug the keyboard into the USB Hub).

Is there any way or switch in the Bios to make the board able to react on keystrokes in the POST phase of a keyboard connected via an usb hub? Or can that feature be implemented in future BIOS.
My former Gigabyte and Asus boards were able to do so.

Regards

Maverick3