4 Port KVM Switch Kit HDMI 4K60Hz with USB 3.0 Docking Station, 4 PCs 1 Monitor

For HKS401-P23 which has a dedicated microphone interface or headset interface, the audio signal is transmitted via the USB channel. Please make sure that you have selected the

correct USB audio device in your computer's audio settings. Typically, USB audio devices

connected to the KVM switch are recognized as "USB Audio Device" on your computer

settings (though occasionally they may be recognized by a different name). Alternatively, you can unplug and plug the audio device to confirm that the newly recognized device is the one you need to select.

• This KVM at 8 Bit colour depth supports

1) 4K@60Hz backwards compatible;

2) 2K@120Hz backwards compatible;

3) 3440X1440@100Hz backwards compatible;

4) 1080P@240Hz backwards compatible.

• Currently HKS401-P23 doesn’t support 5120X1440 resolution for the time being, if your monitor features this resolution, we recommend you to buy another alternative model HKS401-M23.

• Our KVM is compatible with most keyboards. Considering our KVM's keyboard and mouse dedicated ports are equipped with special hotkey chips, there are some typical reasons that may cause compatibility issues:

1)Some keyboard models use proprietary protocols that are temporarily incompatible with the dedicated ports on our KVM.

2)Certain  keyboard  models,  when  plugged  into  the  dedicated  ports  on  the  KVM, consume excessive bandwidth, leading to compatibility issues such as keyboard lag or key sticking.

3)To address these compatibility issues, we recommend customers connect keyboards

that encounter problems when plugged into the keyboard and mouse dedicated ports on the KVM to the USB 3.0 ports on the KVM. The USB 3.0 ports do not have the built-in special chips found in the dedicated keyboard and mouse ports. Plugging your keyboard into the USB 3.0 ports effectively treats it as if it were directly connected to the computer.

• Due to the wide variety of keyboard models available in the market, our R&D department cannot conduct compatibility tests on every keyboard. Below are some keyboard models that have been reported as incompatible by customers: Dell KB813 (and similar keyboards with a card slot), Logitech MX series (some of which cannot manually switch between Windows and macOS modes), Roccat, and certain Microsoft keyboard models.

• There are three kinds of hotkey trigger keys for this product. The default is the [Right-Ctrl] key,  and  the  alternatives  are  the  [Scroll  Lock]  and  [Left-Ctrl]  keys.  However,  HKS401-P23 does not support customizing the hotkey trigger key to any other key,  whereas HKS401-M23 does support this function. You can switch the hotkey trigger  keys to others by:

1)10 seconds after powering on the KVM, press and keep holding the [Select] button on the front panel until you hear the buzzer beeping and the control hotkey is switched.

2)Press the keyboard hotkeys to cyclically switch the control hotkey.

• Please check if your keyboard is plugged into the USB 3.0 port on the KVM. If it is, plug the keyboard into the dedicated keyboard and mouse ports on the KVM instead.
• Try pressing different key combinations to see if the hotkey trigger has accidentally been set to another key. The default hotkey trigger for HKS401-P23 is right-ctrl. Please try pressing scroll lock+scroll lock+1/left-ctrl+left-ctrl+1 to check if it works. Additionally, HKS401-P23  supports changing the hotkey trigger to scroll lock, right-ctrl, or left-ctrl.
• Check if your keyboard has a [Fn] key. If it does, press [Fn]+[right-ctrl]+[right-ctrl]+1/2 to see if it allows normal operation.

For HKS401-P23 which has a dedicated microphone interface or headset interface, the audio signal is transmitted via the USB channel. Please make sure that you have selected the

correct USB audio device in your computer's audio settings. Typically, USB audio devices

connected to the KVM switch are recognized as "USB Audio Device" on your computer

settings (though occasionally they may be recognized by a different name). Alternatively, you can unplug and plug the audio device to confirm that the newly recognized device is the one you need to select.

• Try replacing the cables connecting the monitors to the KVM.
• Attempt to disable HDR and lower the resolution to see if it resolves the issue.
• The quality and length of the cables may be causing the flickering. Consider replacing the  cables with higher quality ones and checking their length. Cable length directly affects the output resolution.

For HDMI cables:

1)   When using 4K@60Hz as the input source, the HDMI cable at the input end should be less than 3 meters, and the HDMI cable at the output end should be less than 5 meters.

2)   When using 4K@30Hz as the input source, the HDMI cable at the input end should be less than 5 meters, and the HDMI cable at the output end should be less than 10 meters.

3)   When using 1080@60Hz as the input source, the HDMI cable at the input end should be less than 10 meters, and the HDMI cable at the output end should be less than 15 meters.