Here is a good summary of Ocatave's history. In the scope of this page we will mostly be concerned with their synth products. The most noteworthy of these being the "Cat" (Well, unless you want to consider the "Eight" which is so extremely rare...) a synth so similar to the ARP Odyssey that well..has basically the same case shape/size... but they each have features the other doesn't. But regardless I've heard some legal proceedings took place mostly over the way the duophonic nature was designed. The Cat is a marvelous machine anyway and thanks to a fellow named Pilgrim up in Canada for donating it to my museum/studio. It's now purring happily.
Besides competing with Moog and ARP with products like this, the company also created the first keyboard that had a 'master controller' kind of connotation, the VPK-5 which was sold to control the Voyetra Eight. Voyetra went on to produce a lot of MIDI software and products, dropping the Ocatave-Plateu name in 1986.

Products:

The Cat Kitten Voyetra Eight