RFC 1091 (rfc1091) - Page 2 of 7
Telnet terminal-type option
Alternative Format: Original Text Document
RFC 1091 Telnet Terminal-Type Option February 1989
IAC SB TERMINAL-TYPE SEND IAC SE
Server requests client to transmit his (the client's) next
terminal type, and switch emulation modes (if more than one
terminal type is supported). The code for SEND is 1. (See
below.)
IAC SB TERMINAL-TYPE IS ... IAC SE
Client is stating the name of his current (or only) terminal
type. The code for IS is 0. (See below.)
3. Default
WON'T TERMINAL-TYPE
Terminal type information will not be exchanged.
DON'T TERMINAL-TYPE
Terminal type information will not be exchanged.
4. Motivation for the Option
On most machines with bit-mapped displays (e.g., PCs and graphics
workstations) a client terminal emulation program is used to simulate
a conventional ASCII terminal. Most of these programs have multiple
emulation modes, frequently with widely varying characteristics.
Likewise, modern host system software and applications can deal with
a variety of terminal types. What is needed is a means for the
client to present a list of available terminal emulation modes to the
server, from which the server can select the one it prefers (for
arbitrary reasons). There is also need for a mechanism to change
emulation modes during the course of a session, perhaps according to
the needs of applications programs.
Existing terminal-type passing mechanisms within Telnet were not
designed with multiple emulation modes in mind. While multiple names
are allowed, they are assumed to be synonyms. Emulation mode changes
are not defined, and the list of modes can only be scanned once.
This document defines a simple extension to the existing mechanisms,
which meets both of the above criteria. It makes one assumption
about the behaviour of implementations coded to the previous standard
in order to obtain full backwards-compatibility.
VanBokkelen