MIDI implementation refers to the specific MIDI messages and signals a piece of gear can recognize; a MIDI implementation chart is therefore a listing of the messages a particular device can transmit and recognize. This can be very useful when attempting to determine if a device can send and/or receive various types of channel or system messages. Normally found in the back of the device’s manual, its MIDI implementation chart will consist of a list of available MIDI messages, whether the device incorporates those messages, and any special notes or limitations on how it deals with those messages. For example, the chart will list the MIDI channels and modes, note numbers, and continuous controllers the device can respond to. Support for aftertouch, velocity, pitch bend (often with bit resolution), and program change will be indicated. Also listed will be recognition of system exclusive, system real time (clock commands), system common (song position, song select, etc.) and aux messages (local on/off, all notes off, active sensing, and so on).