TelnetThis connector is similar to the Socket connector, except that it filters the I/O through the Telnet protocol, as necessary to login to remote servers.
The telnet protocol is very similar to the socket protocol, except that there is some in-band signaling that requires special handling. The telnet port is traditionally 23. See also RFC 854: http://www.faqs.org/rfcs/rfc854.html
The telnet protocol is internally implemented, which is a performance and reliability advantage over launching an external "telnet" command.
The telnet protocol is usually used in conjunction with the "souce.dialog.open" property, to specify a dialog for logging into a remote server and issuing a command which will start the flow of source data over the telnet session.
Because the remote end of the connection is managed by an external telnet server, that server may enforce session limitations (idle timeouts, CPU/memory quotas, etc.) which should be considered.