When Legrand first implemented virtual media in the Dominion KX II, users reported glitches with virtual media drives in the BIOS. Motivated to resolve these thorny functional issues, Legrand engineers went to work developing new and improved KVM switches.
This blog details Legrand's innovative solutions. Take a look and if you're interested in learning more, contact a Legrand expert at DALY to begin transforming your Data Center power chains management with Legrand Dominion switches.
What is BIOS-level access with KVM-over-IP and why does it matter?
BIOS-level access with a KVM-over-IP switch lets you see and control a server from power-on through the full boot process, including the BIOS setup screens—not just after the operating system loads.
With Raritan Dominion KX switches, this means you can:
- Enter and change BIOS settings remotely
- Troubleshoot boot problems when the OS won’t start
- Use virtual media to boot from a remote USB drive, DVD, or ISO image
Because the switch operates at the BIOS level, you can mount media from your laptop and even boot an OS from that virtual drive. This helps IT teams handle OS installs, firmware updates, and recovery tasks without being physically in the data center, which can significantly reduce time to resolution and truck rolls.
How does virtual media work in the BIOS with Dominion KX switches?
Virtual media on Dominion KX switches lets you mount USB drives, DVD drives, or ISO images from your laptop to a remote server over IP. The server sees these as local USB devices, and with BIOS-level support you can:
- Transfer files before the OS is running
- Install or repair operating systems
- Boot directly from a remote ISO or USB image
Early on, some BIOS versions handled USB keyboards, mice, and virtual media in non-standard ways. To address this, Raritan added several capabilities:
- USB Profiles – Predefined combinations of USB settings tuned for specific vendors, models, OSs, and BIOS types (for example, profiles like “BIOS Dell PowerEdge” or “Mac USB-C”). You simply select the profile that matches the target system.
- Dual USB Computer Interface Modules (CIMs) – Server dongles that connect via two USB plugs: one for keyboard/mouse, one for virtual media. Many BIOS implementations handle virtual media more reliably with this separation. These CIMs also support smartcards and digital audio over USB.
- Quick Sense Video Mode – A Dominion KX III video setting that locks onto the server’s video signal faster, helping you reliably catch the brief window to enter BIOS right after a reboot.
- Mouse Synchronization Modes – Alternative mouse modes for cases where the recommended Absolute Mouse Mode doesn’t behave correctly in the BIOS.
Together, these features help Dominion switches support virtual media and input devices across a wide range of BIOS implementations and hardware platforms.
What BIOS settings may need adjustment when using KVM switches?
In many environments, KVM switches work with default BIOS settings. However, there are a few areas that often need attention:
- Wake-up on USB
Some systems require enabling a BIOS option so that a USB keyboard or mouse (connected via the KVM) can wake the machine from sleep or power-saving states.
- Laptop video output for BIOS
On some laptops, the BIOS screen does not appear on the external video port by default. You may need to:
- Enable or mirror the external display in the BIOS
- Set the external port as active during boot
This ensures the KVM sees the BIOS video signal.
- Power behavior after power loss
For integration with remote power control (for example, via an intelligent rack PDU), you may need to change the BIOS setting that controls what the server does when power is restored. Setting it to automatically power on after a power cycle allows you to reboot systems remotely via the PDU.
For detailed steps, Raritan provides product documentation and online help on its Technical Support pages. For system-specific BIOS options, it’s best to consult the server or laptop manufacturer’s documentation.
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