KVM Extender FAQs

KVM Switch Direct has been supplying KVM solutions since 1985 and is an authorised distributor for Adder Technology, Austin Hughes and ATEN. Here are answers to the questions we're asked most often about KVM extenders.

What is a KVM extender and how does it work?

A KVM extender lets you use a computer's keyboard, monitor and mouse from a distance, so the computer can sit in a server room, equipment rack or secure area while the user works somewhere else. It comes as a pair: a transmitter connects to the computer's video and USB ports, and a receiver at the user's desk connects to the keyboard, monitor and mouse. The two units are linked by Cat5e/Cat6 cable, fibre or a computer network.

Moving computers away from the desk reduces noise and heat, improves security and makes maintenance easier. Browse our KVM extenders.

How far can a KVM extender reach over Cat5e or Cat6?

Most KVM extenders reach between 50 and 300 metres over a single Cat5e or Cat6 cable, depending on the model, the video resolution and the quality of the cable. Higher resolutions such as 4K usually reduce the maximum distance, so always check the stated range at the resolution you need.

For best results, use solid-core copper cable rather than patch leads, and avoid copper-clad aluminium (CCA) cable, which is common in cheaper cable and can greatly reduce the working distance. For longer runs, choose a fibre extender or an IP-based extender that runs over your network.

Should I use a fibre or a Cat6 KVM extender?

Choose Cat6 for runs within the cable's range (typically up to 100 to 300 metres) where cost and ease of installation matter most. Choose fibre for longer distances, for electrically noisy environments, or where security is a priority.

Multimode fibre typically reaches several hundred metres and single-mode fibre up to 10 km or more. Fibre is immune to electrical interference, electrically isolates the two ends of the link, gives off no electrical signal that could be intercepted, and is much harder to tap than copper. That is why fibre extenders are widely used in air traffic control, defence and broadcast. If you need a fibre solution, contact us and we'll recommend the right model for your distance and resolution.

Can a KVM extender go through a network switch?

It depends on the type. Point-to-point extenders, including HDBaseT models, use Cat cable but do not use Ethernet, so they must be connected directly to each other and will not work through a network switch.

IP-based KVM extenders, such as ADDERLink® INFINITY and ADDERLink® XDIP, are designed to run over a standard gigabit Ethernet network. They can reach anywhere on your building or campus network, and several receivers can connect to the same computer to form a flexible IP KVM matrix. We recommend running them on a dedicated network or VLAN for consistent performance.

What's the difference between a KVM extender and an HDMI extender?

An HDMI extender sends only the video and audio signal to a remote screen, so it suits displays such as digital signage or a projector. A KVM extender also carries the USB keyboard and mouse signals back to the computer, so you can actually operate it from the remote end, not just view it. Browse our HDMI extenders and KVM extenders.

Is there any lag? Can I use a KVM extender for video editing, design or gaming?

Good quality point-to-point KVM extenders add no noticeable delay, so they feel the same as sitting at the computer. High-end IP extenders such as ADDERLink® INFINITY deliver pixel-perfect, very low-latency video and are used in broadcast, post-production and control rooms.

Some low-cost IP extenders compress the video heavily, which can cause visible lag or blurring on fast-moving images. For video editing, design work or gaming, choose a model designed for high-performance use and check its stated resolution and refresh rate. We're happy to advise.

How many monitors can a KVM extender support?

KVM extenders are available in single, dual and quad-monitor versions. Multi-monitor models send each screen's video to the remote desk, either over one cable or one cable per screen depending on the design. Make sure the extender matches the number of monitors and the connection type (HDMI, DisplayPort, DVI or VGA) of the computer. Browse our DisplayPort, DVI and VGA extenders.

Can I use USB devices other than a keyboard and mouse?

Many KVM extenders only support a keyboard and mouse. Models with "transparent" USB 2.0 also support other devices such as touchscreens, drawing tablets, barcode scanners, USB headsets and memory sticks. If you need to connect anything other than a keyboard and mouse, check the extender's USB specification before buying. Standalone USB extenders are also available if you only need to extend USB.

What is HDBaseT?

HDBaseT is an industry standard for sending uncompressed HD and 4K video, audio and control signals, and on some models USB, Ethernet and power, up to 100 metres over a single Cat cable. HDBaseT extenders are easy to install and widely compatible, but they are point-to-point devices and cannot run through a network switch.

Can I use the existing structured cabling in my building?

Often yes, but with some conditions. The cable must run directly from the transmitter to the receiver without passing through a network switch. Every patch panel, wall socket and patch lead adds signal loss and reduces the maximum distance, so allow a safety margin. The cabling should be solid-core Cat5e, Cat6 or Cat6a, not copper-clad aluminium. If you're unsure, test the extender over the run before committing to a full installation.

Can someone still use the computer locally?

Yes, with many models. Lots of KVM extenders have a local console port on the transmitter, so a keyboard, monitor and mouse can be connected beside the computer as well as at the remote desk. This is useful for maintenance and for shared workstations.

Do KVM extenders need power at both ends?

Usually yes. Most extenders need a power supply for both the transmitter and the receiver, although some transmitters draw power from the computer. Replacement units are available in our power supplies range.

What's the difference between a KVM extender and KVM over IP remote access?

A KVM extender gives a user a dedicated workstation with the same video quality and responsiveness as sitting at the computer, typically in the same building or campus. KVM over IP remote access lets IT staff reach a computer or server from anywhere using a web browser or viewer, including access to the BIOS, but with video compressed to suit the network. It is designed for administration and support rather than full-time use. Browse our remote access products.

Can't find your answer? Call our team on 01372 451345 or email sales@kvmswitchdirect.co.uk, and we'll help you choose the right extender. You may also find our KVM Switch FAQs useful.