Using the UUCP method of transmission, when one computer dials the other it must authenticate correctly before any files are sent. Each computer checks the name of the other to ensure that it is allowed to communicate with it. The calling computer then must enter a correct login and password. Once this has been verified the transmission can begin.
UUCP does NOT allow full control over either computer. When the IMVS dials into your computer, the ONLY option it has is to send files and even then it does not have control over where these are placed. Your computer specifies where they will be placed. (This is set during the initial installation of the UUPC software)