Mike the question has come up on another forum that Hitec does not make a PCM system, yet the Spectra Module - For use with the Lynx 3D Transmitter 24475 at the Hitec site.
http://www.hitecrcd.com/Accesories/spectra75.htm
Clearly shows the module has the words PCM/PPM on the bottom right corner.
The application we are using radio equipment for is Gas Boats, as some of these boats are running at speeds of up to 60MPH + safety is a major concern.