We can take this off line.   As I said, it been done a numberof times with simh and the like.   The key is that simh creates a 'serial line' on a TCP port.    You tell UNIX to hang a login off it and then you telnet or whatever to that port.    The older system running in simh, thinks it has a serial line.   It pretty much just works; al biet is slow as hell and chews up a ton of resources.