via this auction
"This early-80's vocoder/harmonizer has a unique set of sounds and features. Most vocoders do only one thing, but the DVP works as a harmonizer, a pitch shifter, or a MIDI synth. The pitch shifter has a huge range and can be controlled by MIDI, so it works like an early pitch correcter. You can sequence the melody of your vocal tracks! The built-in programmable synth has a whole set of vocal and choral sounds that are useful for pads, leads, or weird bass lines with vocal qualities. The vocoder itself is unique because it is permanently chained to the internal synth, unlike other vocoders that allow a separate carrier input. This vocoder requires a MIDI signal to work. I used a keyboard MIDI controller, but the potential for controlling the vocoded signal with other MIDI devices is vast."Some close-ups of the editable parameters:
