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Network Working Group                                         C. HedrickRequest for Comments: 1079                            Rutgers University                                                           December 1988Telnet Terminal Speed OptionStatus 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 onRFC 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 = 322. 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.Hedrick                                                         [Page 1]

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.,         9600,100Hedrick                                                         [Page 2]

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: HEDRICK@ARAMIS.RUTGERS.EDUHedrick                                                         [Page 3]