I do not nor ever have owned a true PC-98 computer. But I do own an NEC APC III which is equivalent to the original PC-9801 (?). I believe it's safe to make the assumption the keyboards are interchangeable between those 2 models. But few people own both I have to assume, so my question by necessity has to apply to true PC-98 machines and their descendants. To what degree is the first issue keyboard compatible with layer models?