There are three different systems for playing the pipes in a pipe organ. Each system is also known as type of ‘key action’. The first key action is mechanical action, also known as tracker action. In this system, there is a direct mechanical connection between the keys at the console (the place where the organist sits) and the valve for each note. The second is electropneumatic. In this key action there is an electrical connection between the keys at the console and the valves for each note. The valves for each note are a combination of small electrical magnet and a series of two pneumatic valves, thus the name, electro pneumatic. Last is direct electro-mechanical. In the electro-mechanical action there is an electrical connection between the keys at the console and a single electrical valve under each pipe. It is not uncommon for these key actions to be used in combination with each other.