Recording of video images has traditionally been accomplished using VCRs that have been specially designed for the security industry. While these units used standard tapes they were modified to allow for much longer recording time on a single tape by reducing the number of images per second that are recorded on the tape. These systems have been used for many years, but advances in digital recording have made the use of digital video recorders (DVRs) much more commonplace. DVRs have unique performance criteria and terminology, which technicians must understand to do their jobs proficiently.
To determine your level of knowledge of digital video recorders, take our Twenty Questions quiz. Then turn to page 30 to find out how you scored.
1. How many frames per second are generally
perceived as real-time video?