Appendix A. What is True Emulation?

ServSwitch Freedom

True Emulation represents a significant breakthrough in sharing USB devices between two or more computer systems. Until this point, the problem has been how to create a USB switch that provides all of the following:

•Quick, transparent and reliable switching,

•Accurate representation of the connected USB keyboard and mouse,

•Switching control via the connected USB keyboard and/or mouse.

The difficulty in achieving all of the above requirements has been due to the complexity of the USB standard. This has led to vari- ous problems that have spawned a number of possible solutions.

A.1 Enumerated USB switching

The earliest attempts to switch USB devices applied a relatively ‘hands off’ approach. Enumerated USB switches are the electronic equivalent of those old mechanical KVM switches with a large knob on the front.

Enumerated switches are so called because a connected USB device will be required to perform a full initiation (a process called Enumeration) every time it is switched; just as if you had pulled out the plug and then reconnected it.

Enumerated switches simply pass all signals straight through between the USB device and the computer, they do not attempt to interpret any data. For most devices, this offers an advantage because the switch just leaves them to get on with their jobs with- out any interference or any hit on performance. However, it means that a USB keyboard or mouse cannot be used to control the switching process - a quick and simple control method expected by most users. Reliability of switching is also an issue that has plagued enumerated switches, especially when used with certain USB devices and particular operating systems.

A.2 Emulated USB switching

The issues with interpreting the complex USB data streams and recreating (or Emulating) the identity of attached USB devices were eventually solved, leading to the creation of the Emulated USB switch.

A neat side effect of the technique used is that each computer can be fooled into thinking that the USB device is permanently connected to it, even when the device is switched to another computer. This means that the enumeration process for the USB device takes place only once, during the first power on. After that, a computer merely sees a dormant version of the USB device whenever the device is actually connected to a different computer.

However, it remains a complex task to dynamically assume the identity of a USB device, distribute it among the connected com- puters and maintain all of the necessary signals, states and processes. Therefore, manufacturers have previously relied upon a fixed keyboard and mouse profile that is declared to each computer, regardless of the actual connected devices. This precluded the use of any special keyboard or mouse features over and above the standard layouts.

A.3 True Emulation

Mindful of the limitations associated with the previous USB switching techniques, we set about creating a more effective and ele- gant solution. After a great deal of research and development, True Emulation is the result.

True Emulation allows the complete identity of the keyboard and mouse to be copied and then presented to all of the connected computers. This means that any keyboard offering specialist function keys or any mouse with extra features will be fully supported at each computer. As with the previous emulation method, the unselected computers will continue to see the identities of the keyboard and mouse, which means that no enumeration is necessary when their link becomes active once again. This not only helps to speed up the rate of reconnection, but also raises the reliability of switching because USB links are at their most vulnera- ble during the enumeration process.

True Emulation relies upon a high speed circuit, called an Emulation Engine, to fully emulate the USB device identities and also interpret keyboard and mouse data streams. The result is full support for KVM switching control via hotkey presses or the third button/scroll wheel of a mouse.

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KV0004A-XTRA-LED, KV0004A-LED, ServSwitch Freedom, KV0004A specifications

The Black Box KV0004A and its variants, including KV0004A-XTRA-LED and KV0004A-LED, are advanced KVM (Keyboard, Video, Mouse) switches designed to streamline the management of multiple servers and computers from a single console. These devices are pivotal for IT professionals and data centers, providing efficient control over several systems, thereby optimizing workflow and enhancing productivity.

One of the standout features of the KV0004A series is its ability to support up to four computers, making it ideal for environments with limited space or resources. Users can easily switch between connected systems using a simple button, keyboard hotkey, or an On-Screen Display (OSD) menu, which simplifies the operation and minimizes downtime. The KV0004A series supports resolutions up to 1920 x 1200, ensuring clear and sharp visuals during operation, critical for tasks requiring detailed monitoring.

The KV0004A-XTRA-LED model incorporates an enhanced LED interface that provides real-time status updates for each connected computer. This feature enhances visibility and helps users quickly identify active systems, crucial for fast-paced environments where efficiency is paramount. Additionally, the integrated firmware is designed for easy updates, allowing for improved performance and feature enhancements over time.

In terms of connectivity, the KV0004A series supports a wide range of input and output options. It can easily interface with USB and PS/2 peripherals, ensuring compatibility with a variety of devices. In addition, the switches are designed with robust security features, protecting sensitive data being transmitted from unauthorized access, which is essential for any organization working with confidential information.

Another noteworthy characteristic of the Black Box KV0004A series is its plug-and-play functionality, allowing for quick setup without the need for additional software or drivers. This ease of installation means users can get up and running in no time, reducing the potential for errors during deployment.

Lastly, the ServSwitch Freedom adds another dimension by providing true freedom of movement with wireless capabilities. This allows users to operate systems from a distance, greatly increasing flexibility and comfort for system administration tasks. The combination of advanced features, reliable technologies, and user-centered design makes the Black Box KV0004A series a pinnacle choice for effective KVM switching in both enterprise and small business environments.