Thanks for the pointers, ClockWise!
I was under the impession, that Fusion was licenced to Emulators Inc. rather than sold.
Anyway, you will know better. As all apps are available for free these days, its a question of marginal interest.
Who has kept and updated documentation? Emulators Inc. is not likely to have them, as there is nothing on their site.
Microcode offered a lot online. If there was a printed manual, it has not been saved as pdf maybe.
Would be cool to know how Mac serial devices had been used with FusionPC.
Further, I have no idea whether its possible to route a USB dongle´s serial port through DOSBox to Fusion on a OSX host.