White paper - KVM : A new paradigm

Bob Marcus, CEO of RGB Spectrum presents a new white paper entitled: Integrated display plus keyboard video mouse (KVM) control of multiple computers: A new Paradigm.

Multi-input display processors in control rooms are used to present visuals and data in a centralised manner to facilitate group decision making. The multi-input display processor can be either a single screen multiviewer or a multi screen video wall. The processor allows the selection of inputs and the size and position of the windows in which they are displayed. To facilitate comprehension, emphasis can be achieved through positioning and scaling and related information can be juxtaposed. An on-screen cursor may provide control of the processor and serve as a pointer as well. However, conventional systems provide limited mechanisms for controlling the source images themselves. What has been missing is an application that seamlessly blends control of the display space and the source inputs. The techniques described in this paper represent a novel approach to this problem.
As described below, a comprehensive system consists of a control computer, the image sources, and the display processor connected over a network or networks. Image sources may include computing devices as well as keyboard and mouse-controlled video sources such as pan-tilt-zoom (PTZ) cameras or digital video recorders (DVR). Any computer-based device providing video, including data, images, or live feeds, may be considered a source computer. A remote desktop agent is installed on each, configured to communicate with the control computer over an IP network. The control computer is used to configure and manipulate each of the attached devices.
Consider a number of common keyboard, video, and mouse (KVM) applications such as GoToMyPC© and pcAnywhere©. These rely on IP networks for the transport of video as well as control. However, low video resolution and poor response time typically result from the limited bandwidth available on IP networks, though keyboard and mouse input signals can easily be accommodated. But for good video quality, the remote computers may be connected to the display processor through a direct video interface such as Digital Visual Interface (DVI).
RGB Spectrum has developed a novel solution for use with its multiviewers and display wall processors, called Integrated Control System with KvM. This system is a hybrid that uses a combination of direct connection for video and IP connection for keyboard and mouse; hence, the change in nomenclature from the industry-standard KVM to “KvM”. Video inputs are routed directly to the processor and synchronised with control signals provided over the IP network. The hybrid approach provides both high bandwidth for video and flexible data transfers for keyboard and mouse signals. Video over IP may also be accommodated in cases where direct connection of the video is not possible due to distance or otherwise.
Figure 1 is a diagrammatic representation showing an example of an integrated display and control system. The IP control network can be one of a variety of possibilities, the most common being Ethernet.
The display processor, the control computer, and the source computers have unique IP addresses. A remote desktop agent (RDA) is installed on each source computer. Passwords and public-key private-key encryption between the source computer and the control computer are used to create a secure session. Mechanisms such as Transport Layer Security (TLS) and Secure Sockets Layer (SSL) and Secure Shell (SSH) can also be used to provide security.
A complete system also requires an efficient user interface for controlling both the display processor and the source computers. An especially desirable system would offer:
- an on-screen cursor able to range over the entire display
- unified control of the display processor and the source computers with a single mouse, without the need for other devices, physical or otherwise, e.g. on-screen icons or menus
- a keyboard for data input

In RGB Spectrum’s implementation, switching between control of the video processor and the source computers requires only a mouse click.


1. An on-screen cursor provides control of the video processor and the source computers.
a. Switching between the video processors and the source computers requires only a mouse click.
b. On-screen visual cues – the size and shape of the cursor indicates whether the cursor is controlling the video processor or a source computer, based on its x-coordinate and y-coordinate position. For example, the cursor is first enabled in the video processor control mode and it appears on the display as a large arrow.


2. A single mouse controls the display processor and the source computers without the need for other devices, and with no on-screen space devoted to icons or menus.
a. The mouse controls a source computer when the cursor position resides within the window displaying its imagery. Outside of a window, the mouse controls the display processor. The mode of operation switches based on the position of the mouse.
b. When the mouse is in display processor mode, the cursor can be used as a pointer and/or to control the size and placement of windows on the display. For example, with the cursor inside a window, the left mouse button is clicked and held to drag the window to a new position on the display. Placing the cursor on the edge or corner of a window allows it to be resized.
c. With the cursor resides within a window, a mouse click switches mode to operate the computer displayed in the window. A smaller cursor now appears, signalling the mode switch. In addition, keyboard functions are provided by the control computer. Control of multiple computers is easily accommodated: when a cursor moves into one window, the cursor controls the computer displayed there; when the cursor is moved to another window, one click of the mouse and it controls the computer associated with that window.
d. If the cursor is moved outside a window, it goes back to display processor mode and controls the way the source images are displayed. See Figure 2.

3. A single keyboard serves all of the source computers, tracking the state of the mouse.
In short, the user interface is very simple and intuitive. One mouse and keyboard does it all.
In summary, RGB Spectrum’s KvM offers a unified system for the display and control of computers and computer controlled devices. By using direct connection for video coupled with IP control, the hybrid solution allows for the benefits of both, high quality video transport and flexible control. Video quality, including resolution, response time, and frame rate, is dramatically superior to alternatives relying on video over IP. The complete system is operated using a single mouse with an on-screen cursor, and an optional keyboard for data entry. The novel hybrid approach is coupled with the equally novel user interface for seamless, real-time control offering unparalleled responsiveness. A new paradigm is born.

Integrated Control System with KvM is an available option for RGB Spectrum’s MediaWall® multi-screen video wall and SuperView® single-screen multiviewer display processors.
Bob Marcus is CEO of RGB Spectrum.

Article Categories




Most Viewed