RFC1079

Network Working Group C. Hedrick Request for Comments: 1079 Rutgers University

                                                          December 1988

                     Telnet Terminal Speed Option

Status of This Memo

  This RFC specifies a standard for the Internet community.  Hosts on
  the Internet that exchange terminal speed information within the
  Telnet protocol are expected to adopt and implement this standard.
  Distribution of this memo is unlimited.

  This standard is modelled on RFC 930 [1], the telnet terminal type
  option.  Much of the text of this document is copied from that RFC.

Motivation

  Most operating systems have provisions to keep track of the speed
  (bit rate) of directly attached terminals and modems.  This
  information is used to control various timing-dependent display
  processes, e.g., the number of padding characters used for delay.
  Some software also has user interfaces that are tuned differently for
  fast and slow terminals.  The purpose of this option is to provide
  similar information for telnet connections.

1. Command Name and Code

     TERMINAL-SPEED

     Code = 32

2. Command Meanings

     IAC WILL TERMINAL-SPEED

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

     IAC WON'T TERMINAL-SPEED

        Sender refuses to send terminal speed information.

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RFC 1079 Telnet Terminal Speed Option December 1988

     IAC DO TERMINAL-SPEED

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

     IAC DON'T TERMINAL-SPEED

        Sender refuses to accept terminal speed information.

     IAC SB TERMINAL-SPEED SEND IAC SE

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

     IAC SB TERMINAL-SPEED IS ... IAC SE

        Sender is stating his terminal speed. The code for IS is 0.
        (See below.)

3. Default

     WON'T TERMINAL-SPEED

        Terminal speed information will not be exchanged.

     DON'T TERMINAL-SPEED

        Terminal speed information will not be exchanged.

4. 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-SPEED...).

  Once the two hosts have exchanged a WILL and a DO, the sender of the
  DO TERMINAL-SPEED is free to request speed information.  Only the
  sender of the DO may send requests (IAC SB TERMINAL-SPEED SEND IAC
  SE) and only the sender of the WILL may transmit actual speed
  information (within an IAC SB TERMINAL-SPEED IS ... IAC SE command).
  Terminal speed information may not be sent spontaneously, but only in
  response to a request.

  The terminal speed information is an NVT ASCII string.  This string
  contains the decimal representation of the transmit and receive
  speeds of the terminal, separated by a comma, e.g.,

        9600,100

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RFC 1079 Telnet Terminal Speed Option December 1988

  No leading zeros may be included.  No extraneous characters such as
  spaces may be included.

     The following is an example of use of the option:

        Host1: IAC DO TERMINAL-SPEED

        Host2: IAC WILL TERMINAL-SPEED

     (Host1 is now free to request status information at any time.)

        Host1: IAC SB TERMINAL-SPEED SEND IAC SE

        Host2: IAC SB TERMINAL-SPEED IS "1200,1200" IAC SE

     (This command is 15 octets.)

5. Implementation Suggestions

  Many systems allow only certain discrete terminal speeds.  In such
  cases it is possible that a speed may be received that does not match
  one of the allowed values.  We suggest that you pick the nearest
  speed that is allowed, rounding in a "safe" direction.  Safety will
  depend upon the use of the speed information.  If it is being used
  for padding, it is best to round up, since too much padding is better
  than too little.

Reference

  [1]  Solomon, M., and Wimmers, E., "Telnet Terminal Type Option",
       RFC 930, January, 1985

[AAuthor's Address:

  Charles Hedrick
  Rutgers University
  Center for Computer and Information Services
  Hill Center, Busch Campus
  P.O. Box 879
  Piscataway, NJ 08855-0879

  Phone: (201) 932-3088

  Email: [email protected]

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