As explained, each of these technologies has its application, but the technology that unifies the most advantages and that is the most flexible for control rooms are rear projection cubes based on the DLP technology. Depending on the manufacturer, these technologies have more or fewer features, integrated optimising functions, and different quality levels. The main advantage of these large screen displays based on cube technology is the high video density as well as the integrated display of video and data applications. The most important aspects that have to be considered in the selection of cubes for a control centre are: form factor, costs, resolution, brightness, display properties, projector inputs, maintenance costs, and reliability. Cube-based display walls can be used in almost every area, since they can be connected to many various video inputs, can display these signals simultaneously, and can be extended easily. Only very reliable systems come into operation, which have withstood the rigours of continuous operation 24 hours a day, 7 days a week, and 365 days a year. Such systems have been especially designed for this kind of usage. Of course those systems require more space as flat screens, but taking into consideration their advan­tages for the 24/7 operation, space should not be an issue.

The systems are based on the DLP technology from Texas Instruments and were developed for continuous operation. The possibilities and the features of the system are nearly unlimited. The systems offer the following advantages: [10]

• Saving potentials, space, energy, weight.

• Lower service and maintenance costs.

• Functionality.

• Low heat dissipation.

• Free positioning of the windows, scalability.

• Stable geometry.

• High contrast ratio.

• High colour stability.

• Homogenous colour representation over the whole surface.

• Homogenous brightness uniformity over the whole surface.

• Long-term stability.

There are also different options available in such cubes, such as front mainte­nance systems and large screen walls on rails as a space-saving solution for control rooms with limited space. As an alternative it can be stated that LCD monitors with narrow bezels can also be used in control room areas, where the functionalities of these displays meet the requirements.