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First work out which path is failing: video from the computer to the monitor, USB data from the computer to the keyboard and mouse, or the KVM’s switching controls. Those paths can fail independently. A picture can appear while USB is assigned to another computer, and a keyboard can switch while the monitor shows no signal. Check the cables and host selections before replacing anything.
Start by identifying the failed path
Write down the exact KVM, monitor, and computer models, then note what happens on each computer:
- Does the monitor show “No signal,” or is the picture missing only from one computer?
- Do the keyboard and mouse fail on one host or every host?
- Can the KVM’s physical button or the monitor’s on-screen display switch hosts?
Trace video and USB separately. In a setup that uses a monitor with an integrated KVM, video cables connect the computers to the monitor, while separate USB upstream cables may be needed for keyboard and mouse data; shared peripherals connect to downstream USB ports. Dell describes this arrangement for selected monitor models in its KVM setup guide. The exact ports and supported features vary, and KVM functionality is available only on some Dell monitors.
KVM shows no signal
- Select the monitor input for the active computer. Use the monitor’s input/source controls and choose the connector the computer is actually connected to.
- Trace the video cable end to end. Check that the computer’s video output connects to the intended KVM input and that the KVM output connects to the monitor input. Reseat both ends.
- Check any adapter’s direction. Connector shape alone does not tell you whether a video adapter works in the required direction. AV Access notes that HDMI-to-DisplayPort adapter cables are unidirectional in its troubleshooting guidance; verify that the source and display match the adapter’s specified direction.
- Bypass the KVM for a direct test. Connect the computer directly to the monitor using a compatible cable. If there is still no picture, the KVM is not the only link to investigate. Try a known-good compatible cable or another supported monitor input if available.
- Confirm the computer port can output video. A USB-C connector does not guarantee display output. Check the specifications for the exact computer port. ASUS makes this requirement explicit for its XG32VC and XG349C KVM setup.
With two monitors, follow the KVM’s own wiring diagram and check that the computer supports the required display arrangement. Do not assume that a dual-display connection scheme for one KVM applies to another.
#1 Best Overall
- 【KVM Switch 1 Monitors 2 Computers】This HDMI KVM Switch with two HDMI ports allows control of two computers, enabling them to share a single monitor along with keyboard and mouse. It's complete USB switch and HDMI switch rolled into one. This KVM Switch also supports various input devices such as PCs, Laptops, PS4, etc. It is compatible with various operating systems including Windows 7/8/10/11/Vista/XP, Linux, Mac, and more.
- 【Four USB 3.0 Ports (3×USB-A + 1×USB-C)】 This KVM switch features 4 USB 3.0 ports with ultra-fast data transfer speeds up to 5Gbps, including 3 USB-A ports and 1 USB-C port for broader device compatibility. It allows you to seamlessly share peripherals between two computers, reducing cable clutter and improving workspace efficiency. Perfect for connecting and sharing USB devices such as keyboards, mice, scanners, printers, flash drives, headsets, and webcams. The switch automatically detects and recognizes connected devices for stable and reliable performance.
- 【4K Resolution & HDCP 2.2】HDMI KVM Switch supports stunning 4K resolution at 60Hz, ensuring crystal-clear and highly detailed visuals for your monitors. Additionally, it is HDCP 2.2 compliant, allowing you to seamlessly view HDCP-protected content on your monitors without any interruptions. It also supports 4K@30Hz, 2K, 3D, and 1080P, offering flexibility for various display needs. This guarantees both exceptional image quality and a smooth, secure multimedia experience.
- 【Two Ways of Switching】4K HDMI KVM Switch features two switching options: On-KVM Switch Button and Wired Remote Switch. The Wired Remote Switch allows you to place the HDMI KVM switch in hidden or distant location, keeping your desk tidy. Simply place the remote control within easy reach on your desk for quick access. With a press, you can switch between computers seamlessly, enhancing productivity and reducing clutter on your monitors.
- 【Adaptive EDID & Plug and Play】This USB 3.0 HDMI KVM Switch features Adaptive EDID, ensuring stable and smooth image transmission by automatically optimizing display settings on your monitors. Easy to install, this HDMI KVM switch requires no power supply or driver software—just plug it in and connect all cables for seamless operation between two computers and one monitor.
Video works but USB devices do not
- Check the USB upstream path. Make sure each computer is connected by USB to the correct KVM or monitor upstream port. A video cable alone does not carry the USB data path in setups that require a separate upstream connection.
- Connect the peripherals to shared downstream ports. Confirm the keyboard and mouse are plugged into ports intended for shared devices, not into an upstream port.
- Match the USB host to the active video source. Some monitor KVMs select video and USB separately. On the cited ASUS models, select the video source and then its corresponding KVM USB upstream setting; menu labels depend on the model.
- Test the peripherals directly on the affected computer. If they fail there too, try another host USB port. Available functions can differ between ports.
- Try a basic wired keyboard or mouse, or a USB wireless receiver. Peripheral support is model-specific. Dell’s monitor KVM FAQ states, “Bluetooth-enabled keyboards and mouse are not supported,” for its cited monitor guidance—not for all KVMs. TESmart recommends wired devices or USB receivers for its CKS202-P23.
- Check dedicated keyboard/mouse ports. If a device works in a general USB port but not a port marked for keyboard or mouse, consult the KVM’s compatibility notes. TESmart identifies device or port compatibility as a possible issue for its unit.
Keyboard and mouse do not switch
If video changes hosts but the peripherals do not, focus on USB host selection, upstream cabling, and downstream port placement—not the monitor’s video cable. If the keyboard and mouse fail only on one computer, test them directly on that host and check its USB port before investigating the KVM.
If the monitor has its own KVM controls, its selected USB upstream connection may need to correspond to the selected video source. Confirm the setting for your exact model; labels and menu paths are not universal.
Rank #2
- KVM Switch 3 Monitors 2 Computers: This 2*Displayport + 1*HDMI KVM Switches allows you to switch effortlessly between two computers with one click — share 3 monitors and 4 USB 3.0 ports (keyboard, mouse, printer, webcam) without swapping cables. Space-saving KVM for home offices, content creators, and IT professionals. NOTE: Both computers must support triple-monitor output to use all 3 displays simultaneously. If either PC only supports 1 or 2 displays, the extra monitor(s) won’t activate
- Ultra HD 8K@60Hz/4K@240Hz Resolution: This USB KVM switch output features two DisplayPort 1.4 ports + one HDMI 2.1 port, each supporting up to 8K@60Hz resolution, and backward compatible with 8K@30Hz, 4K@240Hz/144Hz/120Hz/60Hz/30Hz. It also supports HDR10+, HDCP 2.3/1.4, VRR, FreeSync, and G-Sync, eliminating screen tearing and stuttering across three monitors, even at high frame rates. NOTE: If need to achieve 8K resolution, your computers and monitors both need to support 8K@60Hz resolution, and please make sure the length of your cables are within 2 meters 28AWG
- Two Switching Ways & Two Dispaly Modes: This KVM switch displayport HDMI supports button switching and desktop controller switching, freely switch between 2 computers. With the desktop controller, you can place this monitor switch for 2 computers outside your work area, making your desktop cleaner and tidier. Two Dispaly Modes, Mirror mode: Triple monitors output the same images, Extend mode: Triple monitors output different images. NOTE: Not support Keyboard shortcuts (hotkeys) toggles
- Wide Compatibility & Package List: This triple monitor KVM switch driver-free and plug and play, and supports Windows, and Linux systems. PACKAGE LIST: 1*KVM switch, 4*DP cables, 2*HDMI cables, 2*USB A cables, 1*power adapters, 1*desktop controller, 1*user guide
- NOTE: 1, To ensure normal usage, please make sure to connect the power supply via the power adapter. 2, To display content across three screens simultaneously, make sure each of your PC is equipped with 2 DisplayPort ports + 1 HDMI port. 3, Each computer at the input needs to be connected with 2* DP cables + 1* HDMI cable+1* USB cable. 4, Please make sure your PC supports 3 screens or above display function before purchasing. 5, If a signal converter or docking station is used, there may be compatibility issues. 6, NOT support EDID emulation
Hotkeys or switching controls do not work
- Try the physical switch button or monitor menu. If it switches successfully, the problem is more likely specific to hotkeys than to video routing or the USB path.
- Check the exact model’s manual. Confirm whether hotkeys must be enabled, which USB port the keyboard must use, and the configured trigger and key sequence.
- Check keyboard compatibility. AV Access lists disabled hotkeys, an incorrect keyboard port, and keyboard compatibility among possible causes in its troubleshooting guidance.
Do not use a hotkey sequence from another manufacturer’s instructions: sequences and settings vary by model.
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USB-C or multiple monitors are involved
For USB-C video, confirm three things together: the computer port supports display output, the KVM supports that connection mode, and the monitors are connected as specified by the KVM maker. ASUS requires display output support on the laptop’s USB-C port for the cited setup.
Rank #3
- 【USB 3.0 KVM Switch with 2 Switching Methods】This KVM Switch 2 Port HDMI can control 2 PCs to share 1 monitor with 1 set of USB 3.0 keyboard and mouse. You can quickly switch between 2 computers, and the KVM switch supports 2 switching methods: wired remote and button switching. Please Note: This product does not support hotkey switching.
- 【KVM Switch HDMI with 3 USB 3.0 Ports】This HDMI KVM Switch comes with 3 USB 3.0 ports for sharing USB devices, such as keybaord, mouse, scanners, printers, U disks and more other USB devices, automatically recognize and match various display devices. This KVM Switches also supports a variety of input devices, such as PC, Laptop, PS4, etc. Compatible with a variety of computer systems like Windows 7/8/10/Vista/xp, Linux, Mac, and so on.
- 【Support Ultra HD 4K Resolution】This KVM Switch 1 monitor 2 computer can support the resolution up to 3840*2160@60Hz, and can also be backward compatible with 3840*2160@30Hz, 1920*1080P@60Hz etc., which will bring you ultra-high-definition visual senses. The 4K KVM Switch can support a maximum refresh rate of 60Hz, please pay attention to the setting of this parameter when you use it.
- 【Adaptive EDID & Plug and Play】This USB 3.0 HDMI KVM Switch can adaptive to EDID, which makes image transmission more stable and more smoothly. Support HDMI 2.0, HDCP2.2 standards. This KVM Switch 2 computers 1 monitor can be easily to install, just plug it in, no power and driver software required. When using this product, please connect all the cables.
- 【After-sales Service】This KVM Switch 2 Port is equipped with USB 3.0 cables(1.2m)*2 , 3.5mm remote control cable (1m)*1, wired remote*1. You need to prepare the 3 HDMI cables required to connect 2 computers and 1 monitor. Our products provide lifetime warranty service. If you have any questions or concerns about our products, please contact us directly through the order number. We will provide you with a solution.
Multi-monitor behavior can also depend on the computer platform and the KVM’s display mode. TESmart’s CKS202-P23 FAQ describes MST-mode and platform limits for that particular USB-C KVM. That model-specific guidance is not a universal compatibility rule or a guarantee about every computer or operating-system version. Check documentation for your computer, KVM, and monitors together.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.When to replace a cable, adapter, or KVM
Replace a part only when a direct connection or a known-good substitution points to that specific link. For example, if the computer displays directly on the monitor but not through the KVM, check the KVM’s input, output, and compatible cable path before concluding the KVM itself has failed. For a suspected USB problem, isolate the upstream cable, host port, downstream port, and device separately.
Rank #4
- Share Multiple USB Devices between 2 Computer : The BENFEI 2 in 4 out USB 3.0 kvm switch supports 2 computers share 4 USB devices like keyboards, mouses, U disk, printers, scanners, USB cameras, headphones, etc. It's convenient for you to switch freely between your work computer and personal computer, driver free and compatible with multiple OS, such as windows 7/10/8/8.1/7/Vista/XP and Mac OS, Linux, and Chrome OS.
- Transfer Files in Seconds: With the 4x USB 3.0 ports, BENFEI USB Switcher supports up to 5Gbps data transfer speed. You can easily transfer data from U disk, mobile hard disk to computer. It's backward compatible with USB 2.0, too.
- Switch Easily: With the USB switcher button and LED indicator design, you can freely switch multiple USB devices between two computers with one click and clearly know the working status. Please note: When connected, it could work only when using the BENFEI USB A to USB A cable.
- Multiple USB Devices Support: BENFEI USB Switch provides an extra USB C(5V 3A) power supply slot. If you use some high power consumption devices such as HDD, USB cameras, headphones, etc, please connect extra power for stable performance. (The USB A-USB Charging cable is included, but the power adapter is not)
- 18 MONTH WARRANTY : Exclusive BENFEI Unconditional 18-month Warranty ensures long-time satisfaction of your purchase; Friendly and easy-to-reach customer service to solve your problems timely
Before buying a replacement video cable or adapter, confirm both connector types and any required conversion direction. Consider an external KVM if the existing unit is faulty or does not support a required capability. Dell identifies an external KVM as an option for monitors without an integrated KVM in its setup guide.
Compare prospective KVMs against the requirements your diagnosis revealed:
Best Value
- 【Dual-Band Wi-Fi 6 Desktop KVM Device】Comet Pro supports both 2.4 GHz and 5 GHz Wi-Fi bands for a cleaner setup with less cabling. By providing both wired and wireless connectivity, it eliminates single points of failure and redefines flexibility for remote access.
- 【4K Video Passthrough & Two-Way Audio】The GL-RM10 features 4K@30FPS video passthrough and two-way audio, delivering ultra-clear, low-latency streams via H.264 encoding without interrupting the local display. Its audio support ensures crystal-clear voice interaction —ideal for remote meetings and IT support to create a natural "face-to-face" experience.
- 【Touchscreen Interface】The 2.22-inch built-in touchscreen features an intuitive user interface that is easy to operate and requires no technical expertise, allowing you to effortlessly view and manage important functions—such as connecting to Wi-Fi networks and enabling or disabling cloud services.
- 【Built-in Tailscale】 Enables secure, efficient data transfer between devices using WireGuard's encrypted transmission and direct connection features. Ideal for home labs, offices, and multiple networking scenarios.
- 【Flexible Remote Access】Remote access can be achieved through our web based cloud control functionality, supporting Windows, macOS, and Linux systems without needing to install any software. Additionally, there is remote support via the GLKVM app available to Windows, macOS, iOS and Android devices.
- Computer and monitor connector types, including any conversion direction.
- Number of computers (hosts) and monitors.
- Required resolution and refresh rate supported across the full computer–KVM–monitor connection.
- Whether USB switching needs separate upstream cables or uses a supported USB-C connection.
- Required keyboard, mouse, and other USB devices, including any dedicated-port restrictions.
- Any specific hotkey, EDID, or multi-stream feature needed for your setup.
Check the manufacturer’s specifications for the exact model; no one KVM brand or model is established as the best choice for every setup.
Quick Recap
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