Cham-Ber Huang was the inventor of the Chordomonica I & II . His patent request for the Chordomonica II was granted in 1968 with patent# 1255465. Some brief info of the patent can be found on Pat Missin’s side as well as an extensive explanation of the tuning for both models.
Since 1981 Hohner discontinued the production of both models.
The patent ran out in 1983. There are now some different custom version of the Chordomonica available.
4 and 3 Octave version using the standard Chromonica cover plates
There is also a Chordomonica project website with another custom version using a customized Hohner Discovery 48.