Telnet turned a network connection into an interactive terminal session: keystrokes travel to a remote shell, output streams back. It powered remote administration, library catalogs, and BBS access before SSHSecure Shell — encrypted remote login, command execution, and file transfer over networks.. The protocol's option negotiation (echo, linemode, terminal type) became a template for layered network services.

Telnet was the first widely deployed remote-login standard on TCPTransmission Control Protocol — a reliable, connection-oriented protocol used on the internet./IPInternet Protocol — the addressing and routing layer that moves packets across networks. networks.

It proved interactive terminal sessions could ride on packet networks — paving the way for SSHSecure Shell — encrypted remote login, command execution, and file transfer over networks. and remote ops culture.