Electrically operated burglar alarm system - is disabled by inputting combination in push button keyboard having supplementary push button for cancelling wrong combinations

摘要

A pushbutton control for a burglar alarm system comprises a control box (P) containing a pushbutton keyboard. The combination to switch off the system is punched in on this. A supplementary pushbutton (M) enables mistaken combination inputs to be cancelled. The pushbuttons are hidden behind a key-locked panel. The supplementary pushbutton controls a counter which counts the number of false combinations tried and after a preset count is reached inhibits the pushbuttons and activates an alarm (S) or a camera (K). The counter may be reset to zero by a pushbutton (Z) on a control panel inside the protected area. The pushbutton keyboard also includes indicators (H, J) to show when the correct combination and a wrong combination have been entered.