The first model, introduced in 1985, was the Pad-8. It was an influential device at that time, allowing drummers and percussionists the opportunity to trigger virtually any MIDI sound source without the need of a full electronic drum set. It had no internal sound source, and all pads were assignable to one note each. All pads were on the same MIDI channel.
The second model, introduced in 1989, was the Pad-80 Octapad II. Again the Pad-80 was an eight pad MIDI controller that allowed for various types of MIDI sound sources. Improvements in this second model included the ability to play up to three notes per pad, and velocity switching, which allowed the user to stack or alternate between the assigned notes depending on how hard the pads were struck. This feature became useful for creating more realistic sounding drum parts, and in addition allowed drummers to play melodic instruments with greater ease. These new features were groundbreaking at the time, and are still utilized in Roland’s electronic percussion today.