Control centre for intruder alarm system - uses counter to address sequential gates with inputs from intrusion sensors

摘要

A number of detectors are connected in series to a tristate gate. Other tristate gates receive inputs from a timing control and from photodetectors. A counter sequentially addresses the dates to provide an input signal for a memory. The gate outputs pass through a programmable logic gate then via a programmable timer to a selector circuit. Instructions pe for programming and selection actions are controlled from the counter. A keyboard and control unit permits initialisation of the system and contains a display panel for visual indication of an intrusion. An amplifier in an alarm unit operates a relay to power an audible alarm. An interface permits connection to a telephone line for remote signalling purposes.