Asterisk integration to Marriott FOSSE PMS

Does anyone have access to technical documentation for Marriott’s proprietary PMS? We need to write some code that will facilitate serial data communication to/from the FOSSE system and our Asterisk PBX, but at the moment we lack basic information about how to structure it. Marriott management has been very unhelpful.

Very difficult to find this information or any document on the subject.