The pipes are grouped into several separate sections called divisions. Each one has a name and is controlled through it's own manual or the pedalboard. There is only one Pedal division. These turn the different kinds of pipe sounds on or off. Pulling the knob out turns the stop on and pushing it in turns it off.
Some builders use stop tabs which flip up and down.
In an electric key action, a wire, an electrical circuit and an electro magnet cause the valve below each pipe to open and close. When you press the key, you close an electrical contact. Electricity flows to the circuit which causes an electro magnet to open and close the valves under each pipe. This is a piece of metal which, when magnitized by an electrical circuit , attracts the valve below the pipe. The valve opens and air flows through the pipe, making the pipe speak .