I ran across a scenario where a customer wanted to dump log files and have them collected and parsed as usual, but did not want to use the SFTP agent. I explained that the File Reader service checks periodically (60 seconds by default) for new files that are deposited into the directory structure, then deletes the file so that no new files that are deposited will conflict with the existing files.
If you have another mechanism that will get the files to the correct destination (like scp, FTP, mapped drives,etc.), then you can:
Set up the ftp service from enVision like you normally would then drop the files in the appropriate sub folder under the ftp_files directory.The enVision appliance still needs to know that it will be receiving files in the ftp_files location. So from the enVision standpoint it has to have the right configuration to read the files in. The ftp service may not need to be started, but the file reader needs to be configured to read files in that location.
DO NOT FORGET that you will need some mechanism to ensure that the files are periodically transferred over, like a script that uses AT commands or some other batch job process.