Experience gathered during the development, and operation, of a nationwide mobile digital communications system

The direct dialogue with the computer from a moving vehicle or small hand-held unit has been day-to-day routine for many security officers in the Federal Republic of Germany for quite a while. The development effort made over the past few years has led to matured systems. Based upon commercially available technology, it comprised, for the most commonly used digital communications system, the following areas of study: - simplifying data terminal operation, - ergonomics and secure mounting in vehicles, - data display on the screen of the mobile terminal in a form compatible with user needs and system requirements, - implementing an operating system for wireless digital communications systems covering large areas and - concomitant field, and laboratory, testing to evaluate the performance characteristics of digital communications systems made by different manufacturers. The experience gathered during this work and the technological state of the art are described in the present paper.