The USER i5/OS® FTP server subcommand sends a user logon ID to the FTP server. If the USER subcommand is successful and the system is configured for password security, the FTP server sends a reply to the client and requests a password.
USER username
When requested by the FTP server, the client sends the password to the FTP server with the server subcommand PASS. No password prompt occurs when the FTP server is running at security level 10.