Additional settings / "TCP/IP" tab ([Setup] menu)

Save history when new connection

If this option is selected, a host name entered in the [File] New connection dialog box is appended to the top of host list.

Edit history

Edit History.

Telnet

Use the telnet protocol. Usually, you should select this option.

TCP/IP Port#

TCP port number.
22: SSH
23: Telnet

Keep alive

This feature is called by Telnet keep-alive(heart-beat) mechanism. If this feature is enabled, Tera Term will send NOP message(IAC NOP: 255 241) periodically. 0 to turn off. The default value is 300 seconds.

Auto window close

Closes Tera Term when the connection is closed.

Terminal type

Terminal type to be reported to the host when the telnet connection is established.
When TermType is set to "xterm" the applications (e.g. vim6) supporting ANSI color will appear in color. This function is from the original Tera Term.
You should specify "vt100" or "ANSI" for Windows Telnet Server. "xterm" will cause a problem.