RFC 729 (rfc729) - Page 1 of 1


Telnet byte macro option



Alternative Format: Original Text Document



Network Working Group                               Dave Crocker, Rand-ISD
Request for Comments: 729                        (Dcrocker at Rand-Unix)
NlC: 40306                                       13 May l977




                        TELNET Byte Macro Option


1. Command name and code:

   BM 19

2. Command Meanings:

   IAC WILL BM

        The sender of this  command REQUESTS or AGREES  to use the  BM
        option, and will send sing1e  data characters which are to  be
        interpreted as if longer data strings had been sent.

   IAC WON'T BM

        The  sender  of  this  option  REFUSES  to  send  single  data
        characters which  are  to be  interpreted  as if  longer  data
        strings had been sent.

   IAC DO BM

        The sender REQUESTS or AGREES to have the other side (send  of
        WILL BM) issue  send single  data characters which  are to  be
        interpreted as if longer data strings had been sent.

   IAC DON'T BM

        The sender REFUSES to allow the other side to send single data
        characters which  are  to be  interpreted  as if  longer  data
        strings had been sent.

   IAC SB BM  IAC SE
        where:

            is the  data byte actually  to be sent  across
           the network; it may NOT be Telnet IAC (decimal 255).


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            is a  one-byte binary number,  indicating how  many
            characters follow, up to the ending  IAC
           SE, but not including it.

            is a string of one or more Telnet  ASCII
           characters and/or commands,  which the  is  to
           represent; any  character may  occur within  an  .

        The indicated    will  be  sent  instead  of  the
        indicated . The receiver of the 
        (the sender  of the  DO BM)  is to  behave EXACTLY  as if  the
         of bytes had instead been received from the
        network. This  interpretation is  to  occur before  any  other
        Telnet interpretations, unless the  occurs as part
        of a BM subcommand; in this case no special interpretation  is
        to be made.

        Note that the effect of a particular  may be
        negated by reseting it to "expand" into itself.

         is decimal 01.


   IAC SB BM  IAC SE

        The receiver  of the   for    accepts  the
        requested definition and will perform the indicating expansion
        whenever a   is received and is  not part of a  BM
        subcommand.

         is decimal 02.


   IAC SB BM  IAC SE

        The receive  of  the   for    refuses  to
        perform  the  indicated  translation  from     to
         either because the particular 
        is not  an acceptable  choice  or because  the length  of  the
         exceeds available storage.

    is decimal 03.

    may be

            which is decimal 01; or

            which is decimal 02.


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   IAC SB BM  IAC SE

        The  is to be treated as real data, rather than as
        representative of the  is decimal 03.




3. Default:

   WON'T BM -- DON'T BM

        No reinterpretation of data is allowed.

4. Motivation for the option:

   Subcommands for Telnet options currently require a minimum of  five
   characters to be sent over the network (i.e., IAC SB