Telnet terminal type option (RFC0884)

Network Working Group Marvin Solomon Request for Comments: 884 Edward Wimmers University of Wisconsin - Madison December 1983

TELNET TERMINAL TYPE OPTION

This RFC specifies a standard for the ARPA Internet community. Hosts on the ARPA Internet that exchange terminal type information within the Telnet protocol are expected to adopt and implement this standard.

1. Command Name and Code

TERMINAL-TYPE 24

2. Command Meanings

IAC WILL TERMINAL-TYPE

Sender is willing to send terminal type information in a subsequent sub-negotiation

IAC DO TERMINAL-TYPE

Sender is willing to receive terminal type information in a subsequent sub-negotiation

IAC DON’T TERMINAL-TYPE

Sender refuses to accept terminal type information

IAC WON’T TERMINAL-TYPE

Sender refuses to send terminal type information

IAC SB TERMINAL-TYPE SEND IAC SE

Sender requests receiver to transmit his (the receiver’s) terminal type. The code for SEND is 1. (See below.)

IAC SB TERMINAL-TYPE IS ... IAC SE

Sender is stating the name of his terminal type. The code for IS is 0. (See below.)

Solomon & Wimmers [Page 1]

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 be...