Centralized control of the rescue alarm circuit

The centralized control call for help alarm circuit can be used for hospital bed calls, and can also be used for anti-theft alarms in multi-story buildings, dormitories, warehouses and other places
. The circuit is shown in Figure 13-64. Three monitoring positions are drawn in this circuit, but there can actually be many monitoring positions. The circuit
uses thyristor control, KD9 561 or CW9561 simulates sound integrated circuit A for alarm, and LED for position display. Alarms can be controlled
from different locations .