How to Choose the Right KVM Extender?

Time : May. 11, 2023    View : 29

When it comes to remote computer control, the KVM extender plays a crucial role. It effectively addresses the limitations imposed by HDMI, DisplayPort, and USB cables by extending KVM signals over varying distances, ranging from 15 feet to several miles. Its applications span across diverse fields such as industrial control centers, broadcasting, education, healthcare, and more. To ensure you make an informed purchase, here are some key factors to consider when selecting a KVM extender.

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Essential Considerations for a KVM Extender

1. Evaluating Video Connectivity and Resolution

The first step is to assess the video connectivity options and resolution capabilities. Resolution refers to the number of pixels displayed on a monitor, directly impacting image clarity and sharpness. It is important to ensure that the KVM extender supports the resolutions required by your displays and source systems, such as 4K@60 or 1080P@60.


Additionally, consider the video interface provided by the KVM extender, with HDMI and DisplayPort being the most commonly used interfaces. These interfaces have specific specifications, including maximum supported resolutions per revision, required bandwidth, and high-bandwidth digital content protection (HDCP) revisions. For instance, if you need to extend a 4K UHD display running at 60Hz, you’ll require a KVM extender that supports a video connector compliant with DisplayPort 1.2 or higher, or HDMI 2.0 or higher. However, for lower resolutions like 2560×1600, a KVM extender compatible with DisplayPort 1.1 or HDMI 1.2 will suffice.


2. Verification of USB Device and Peripheral Support

KVM extenders can effectively extend various USB devices. While keyboards and mice are the primary USB devices, it is also possible to extend USB flash drives and USB audio devices. USB devices are categorized into USB HID devices, USB 2.0 devices, and USB 3.0 devices, each supporting different types of transfers. Before purchasing a KVM extender, ensure that it supports all the necessary types of USB devices and other peripheral signals required for your specific setup.


3. Ensuring Audio Device Compatibility

Most KVM extenders provide a combination of connectors that support both analog and digital audio devices. For example, line-in connectors are suitable for connecting amplified analog audio sources like audio mixers, while 3.5mm jacks are used for unamplified audio signals, such as microphones or headphones. In addition, USB ports with isochronous data transfer capabilities can connect digital audio devices or USB headsets. Both DisplayPort and HDMI video connectors can carry digital embedded audio from the system to the display.


4. Determining Transmission Medium

Distance and Bandwidth KVM extenders utilize either CATx or fiber optic cables as transmission mediums. The choice of cable determines the available bandwidth and maximum transmission distance.


CATx cables are commonly used in Gigabit Ethernet local area networks (LANs). Typically, CAT5e cables have a maximum distance limitation of 100m/328ft in point-to-point connections. KVM over IP installations can take advantage of the longer distances provided by CATx cables when passing through multiple routers and switches. (What is the difference between KVM extenders and KVM over IP?) In contrast, fiber optic cables offer much longer transmission distances compared to CATx cables in point-to-point connections. For example, fiber optic SFP+ cabling can cover up to 10 kilometers/6.21 miles.


Transmission mediums have bandwidth limitations, and higher-resolution video signals require higher bandwidth. CAT5e cables offer the necessary bandwidth support for extending uncompressed 1080p60 video, but resolutions higher than 1080P@60 are not possible due to the greater bandwidth they require. For instance, uncompressed 4K UHD resolution video (2160P60) demands more than the 10 Gbps bandwidth supported by CATx cables. In such cases, you can use KVM extenders that utilize compression to reduce data size and fit within the available bandwidth. Other alternatives include running multiple cables or opting for KVM extenders with higher transmission bandwidth.


Prior to purchasing a KVM extender, it is important to consider the key factors mentioned above. By understanding your specific needs in terms of video, USB, audio, transmission distance, bandwidth, and any other unique requirements, you can make a well-informed decision and potentially save money in the long run. This approach allows you to determine exactly what you need and avoid purchasing unnecessary equipment. We hope that this article proves useful in guiding you toward selecting the most suitable KVM extender for your particular needs.