Guides & Articles

KVM Extenders: FAQs

In this FAQ, you will find answers to some basic questions about KVM extenders. Read on to learn about what they are, how they work, where they are used, their benefits, the maximum distance that signals can be extended, and more.
 

What is a KVM extender? What does a KVM extender do?

A keyboard, video, and mouse (KVM) extender enables users to work on a computer from a distance. Typically, it is a set of transmitter and receiver appliances. The KVM transmitter unit is connected to the computer system and captures the peripheral signals such as universal serial bus (USB) for keyboard and mouse, audio, and video. These signals are extended to a remote user station where the monitors, keyboard, and mouse are powered by the KVM receiver unit. KVM extenders overcome the distance limitation of HDMI®, DisplayPort™, and USB cables and transport these signals anywhere from 15 feet to several miles away from the system.

How does a KVM extender work?

KVM extenders consist of a transmitter and receiver pair. A transmitter unit is located next to the computer system, and a receiver unit resides at the remote user station. The units communicate with each other over copper (such as CAT5e) or fiber optic cabling.
 
The KVM transmitter unit captures the input/output (I/O) signals from the computer—while the most common signals are video, audio, and USB for control, some models also extend RS232 and infrared (IR) signals. The KVM extender encodes these signals and uses either proprietary or standard internet protocol to transport them to the KVM receiver unit, which decodes these signals and powers the remote peripheral devices (such as displays, keyboard, mouse, and speakers).

What are the benefits of using KVM extenders?

A KVM extender is useful wherever there is a need to control a computer from a distance—which could be for a variety of purposes. The most common reasons to use a KVM extender include user comfort and safety, centralization of equipment for security and easy maintenance, and enabling/improving collaborative efforts. When a user needs to work on more than one system, using KVM extension with switching solutions declutters and optimizes desk space—since multiple computers can be controlled with a single set of displays, keyboard, and mouse.

Where are KVM extenders used?

KVM solutions are deployed in a wide range of industries and control room applications to improve security, ergonomics, and collaboration—from industrial control rooms to military and defense command centers, airport management, transportation, emergency dispatch centers, post-production, broadcast, education and healthcare, to name but a few.

What are IP KVM extenders?

IP KVM extenders enable users to work on a computer from a distance. They use internet protocol to transmit signals from point A to point B, convert the signals into packets, and distribute them through standard commercial off-the-shelf (COTS) network switches. IP KVM extenders offer many advantages over point-to-point KVM extenders. They enable the design of KVM matrix systems over IP, where any source system can be accessed from any remote location on the network. The network switch effectively replaces the traditional KVM matrix switch and provides better scalability.

What is a KVM switch? How is it different from a KVM extender?

KVM switch is a hardware device that allows a single user to control multiple computers with a single set of displays, keyboard, and mouse attached to the KVM switch. The primary goal of the KVM extender on the other hand is to extend the video, keyboard, mouse, audio, and USB signals of the system to a remote user station. IP KVM extenders support both of these functions—they extend the KVM signals over IP and allow users to control multiple computers from a single set of displays, keyboard, and mouse attached to the KVM receiver unit. With IP KVM extenders, the network switch effectively replaces the fixed-port KVM switch.

What cable types are supported for transmission?

Typically, two types of KVM extenders can be found—those that support fiber optic cabling, and others that support CATx (copper wire) cabling. Some KVM extenders can support both types of cabling. The type of cabling required will be dictated by the distance the signals need to be extended (fiber optic cables support the longest distance), the environmental conditions, and the security level required (fibre optic cable is immune to electro-magnetic interface and considered more secure).

What is the maximum distance that the signals can be extended?

This depends largely on the cabling and the design of the KVM extender. As a general guideline, CATx cables support a maximum distance of about 100 meters (328.08 feet) in point-to-point extension, while IP KVM extenders support longer distances over CATx networks. Fiber optic cables provide a quantum jump in distance supported than CATx—for example, fiber optic single-mode cabling can cover up to 10 kilometers (6.21 miles).

What are the common video connection standards?

DisplayPort and HDMI are the most common video connection standards available on modern graphics cards and displays. The HDMI and DisplayPort specifications establish the maximum supported resolution per revision, the required bandwidth, and the corresponding high-bandwidth digital content protection (HDCP) revision.

What is HDCP?

HDCP is a hardware encryption specification that protects digital content from being transmitted to non-compliant devices and prevents the unauthorized duplication of the content.

How many monitors can I extend with a KVM extender?

Select high-performance KVM extender models support multi-display configurations, extending up to four video signals with a single transmitter/receiver pair over a single fiber-optic or CATx cable. To support higher number of displays, multiple KVM extenders can be used with a system.

Why does bitrate matter in IP KVM installations?

Bitrate measures the amount of data transmitted per second, generally in megabits per second (Mbps). It indicates the amount of bandwidth an IP KVM extender requires for transporting audio, video, and USB signals over the network. Evaluating the available network bandwidth is critical in planning and deploying an IP KVM solution.

What type of security features do IP KVM extenders support?

IP KVM extenders could offer several security features, such as encryption to protect the confidentiality of the information transmitted, and user authentication to prevent unauthorized remote access to systems.

Can a user access multiple computers with IP KVM extenders?

Yes. Select IP KVM extender models support many-to-one configurations. A user can control multiple systems from a single receiver unit (remote user station).

Can multiple users access the same computer with IP KVM extenders?

Yes, select IP KVM extender models support one-to-many configurations. Multiple users can access the same computer system from different receiver units (different remote user stations).

Can I switch between two computers running different operating systems (for example, Windows® and Linux®)?

Yes, select IP KVM extenders are compatible with multiple operating systems, and they allow switching between two computers each running a different operating system. A user can then work remotely on these computers from a single receiver unit that powers single set of displays, keyboard, and mouse.
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