The past 30 years have brought significant changes in the application of security electronics and communications technologies to support the operational and security functions of correctional facilities. During the early 1970s, technology within a standard correctional facility was primarily limited to relatively simple systems to support door control and monitoring functions, and limited closed-circuit television functions, intercom systems and public address systems. The systems were generally structured as "stand-alone" systems. For example, door control systems were typically relay controlled or directly hard-wired, and the system typically would have been a product manufactured by one of the door lock manufacturers. In general, intercom and paging systems were furnished and installed by a subcontractor specializing in audio systems, while closed-circuit television systems were furnished and installed by another subcontractor specializing in those systems.
Today, the structure of security electronics and communications systems has changed significantly. Products are available that reflect significant technological advancements over those products available 30 years ago, and new products are constantly being introduced that must be considered for current and future applications.
The following will address selected technologies or products and the significance of the changes in the products or the development of new products or technologies that have impacted the structure and operations of security systems today as compared with systems incorporated into the correctional facility security system designs of the 1970s. Space limitations for this article preclude an extensive survey of this subject, and the absence of a specific product or technology from this material does not imply a lack of significance of the product or technology. In addition, the sequence of presentation for each of the following subjects does not weigh on the significance of the product or technology since all system components support the security and operational objectives of a correctional facility.
Controllers (Monitoring and Control)
In the early 1970s, controllers (1) for correctional facility operations were generally custom designed and employed by electromechanical relays used to perform logical functions. These controllers were generally hard-wired and provided little or no flexibility for changes and they were not networked.
By the mid to late 1970s, solid state controllers were introduced, which generally provided a means to program or modify monitoring and control functions by programming software associated with a microprocessor. Typically, changes in the logical functions would require burning the software into an EPROM (erasable programmable read-only memory) chip.
Controllers that were prevalent during the mid-1970s to mid-1980s were generally a custom product of a company that developed a product for primary use within a correctional facility or the product may have been a customized application of a product designed for other applications. For example, several of the manufacturers of control systems for the heating and air conditioning applications provided controllers for correctional facility applications. Essentially, all customized controllers incorporated proprietary software and features that impacted the procurement and maintenance process. The customized controllers incorporated programmable features and provided a means to network multiple controllers. In turn, the networking provided a means to practically and economically monitor and control devices from a remote point, which facilitated a more flexible monitoring and control structure for security staff.
By the mid-1980s, programmable logic controllers that were primarily designed and manufactured to support automated controls within the automobile manufacturing, petroleum and general industries, became economical and exhibited features and characteristics that would support the security functions of a correctional facility. A significant feature of the controllers was that the logical functions required were programmed via the use of ladder logic, which...