Q: “What are the differences between the two pedal jacks on the back of my new keyboard?”
A: For the most part, there are two types of pedal jacks on back of today’s keyboards. One is for connection of on/off controllers (often called a footswitch or momentary switch-type controller) and the other is for the connection of a continuous controller (sometimes referred to as foot controllers).
An on/off controller is most often used to control (or turn on and off) sustain. Other forms of assignable on/off parameters include portamento, increment or decrement of a voice/patch, start/stop of a sequencer, holding an arpeggiator on or off. These on/off parameters will be defined by your particular keyboard.
The continuous controller jack allows you to connect foot controller that controls one of various different assignable functions (depending upon your keyboard) such as volume, pan, pitch, a filter, or other aspects of the sound. By using a foot controller for these parameters, your hands are free to play or operate other controllers, which can be a necessity when playing out live!