I am not even really sure what that means. But if you are looking for a good cross-platform communication protocol have you looked at SOAP (aka, using web services). Both the Microsoft and Java platforms support web services and they are not that hard to use.
Can any recommend a cross platform free serial comms api targetting windows/mac/linux ?
Thanks,
The Java Communications API is the "official" API, but unfortunately the reference implementations are reputedly poor, and Sun doesn't ship a Mac or Linux version. But these guys support multiple platforms with a far nicer implementation.