Reference: Standard FTP Server
Administration
Encryption Services
Enable Standard FTP Server
Secure, FTPS connections are automatically enabled when the standard FTP server is started. These connections are automatically negotiated when a call is received on port 990. Calls received on the clear text port may be reconfigured to secure connections using the AUTH command.
The server supports all versions of the SSL and TLS protocols. Beyond FTP provides a default certificate. You may provide your own as described in the tutorial.