RFC 884 (rfc884) - Page 2 of 5
Telnet terminal type option
Alternative Format: Original Text Document
RFC 884 December 1983
3. Default
DON'T TERMINAL-TYPE
WON'T TERMINAL-TYPE
Terminal type information will not be exchanged.
4. Motivation for the Option
This option allows a telnet server to determine the type of terminal
connected to a user telnet program. The transmission of such
information does not immediately imply any change of processing.
However, the information may be passed to a process, which may alter
the data it sends to suit the particular characteristics of the
terminal. For example, some operating systems have a terminal driver
that accepts a code indicating the type of terminal being driven.
Using the TERMINAL TYPE and BINARY options, a telnet server program
on such a system could arrange to have terminals driven as if they
were directly connected, including such special functions as cursor
addressing, multiple colors, etc., not included in the Network
Virtual Terminal specification. This option fits into the normal
structure of TELNET options by deferring the actual transfer of
status information to the SB command.
5. Description of the Option
WILL and DO are used only to obtain and grant permission for future
discussion. The actual exchange of status information occurs within
option subcommands (IAC SB TERMINAL-TYPE...).
Once the two hosts have exchanged a WILL and a DO, the sender of the
WILL TERMINAL-TYPE is free to transmit type information, spontan-
eously or in response to a request from the sender of the DO. At
worst, this may lead to transmitting the information twice. Only the
sender of the DO may send requests (IAC SB TERMINAL-TYPE SEND IAC SE)
and only the sender of the WILL may transmit actual type information
(within an IAC SB TERMINAL-TYPE IS ... IAC SE command).
The terminal type information is an NVT ASCII string. Within this
string, upper and lower case are considered equivalent. A few
terminal type names useful in the context of IBM systems are listed
below. It is anticipated that additional names will be added in the
future. The complete list of valid terminal types will be found in
the latest "Assigned Numbers" RFC.
Solomon & Wimmers