Telnet, RSH, and FTP are all examples of what?

All of these protocols are unsecure. FTP has been replaced by secure versions in some uses (SFTP/FTPS), whereas Telnet has been superseded by SSH in modern applications. RSH is outmoded and should be seen only on truly ancient systems. If you find a system or device exposing these protocols, you will need to dig in further to determine why they are exposed and how they can be protected if they must remain open for a legitimate reason.