How to Control Them
The push button is the most common means of control. You can use one button to control several bells, or several buttons to control one bell, or have several buttons control several bells. Because low voltage is used, adding extra buttons is simple, inexpensive, and safe.
Buzzers and bells can also be controlled by: clocks, as in the interval timer on an electric range or in a school class bell system; temperature detectors, as in a fire alarm or freezer alarm; door and window trips, as in a one-man repair shop or in a burglar alarm; and treadles, as in the driveway of a service station.
Figure 2