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rfc:rfc657

D. Crocker (UCLA-NMC) RFC 657, NIC 31160 (Oct. 25, 1974) Online file: [ISI]<DCROCKER>NAOVTD.TXT

          TELNET OUTPUT VERTICAL TAB DISPOSITION OPTION

1. Command name and code

 NAOVTD 15
    (Negotiate About Output Vertcial Tab Disposition)

2. Command meanings

 In the following, we are discussing a simplex connection, as
 described in the NAOL and NAOP Telnet Options specifications.
    IAC DO NAOVTD
       The data sender requests or agrees to negotiate about output
       vertical tab character disposition with the data receiver.
 In the case where agreement has been reached and in the
 absence of further subnegotiations, the data receiver is
 assumed to be handling output vertical tab character considerations.
    IAC DON'T NAOVTD
       The data sender refuses to negotiate about output vertical tab
       character disposition with the data receiver, or demands a
       return to the unnegotiated default mode.
    IAC WILL NAOVTD
       The data receiver requests or agrees to negotiate about output
       vertical tab character disposition with the sender.  In the
       case where agreement has been reached and in the absence of further
       subnegotiations, the data receiver alone is assumed to be
       handling output vertical tab character considerations.
    IAC WON'T NAOVTD
       The data receiver refuses to negotiate about output vertical
       tab character disposition, or demands a return to the unnegotiated
       default mode.
    IAC SB NAOVTD DS <8-bit value> IAC SE
       The data sender specifies, with the 8-bit value, which party
       should handle output vertical tab characters and what their
       disposition should be.  The code for DS is 1.
    IAC SB NAOVTD DR <8-bit value> IAC SE
       The data receiver specifies, with the 8-bit value, which party
       should handle output vertical tab characters and what their
       disposition should be.  The code for DR is 0.

3. Default

 DON'T NAOVTD/WON'T NAOVTD
    In the default absence of negotiations concerning which party,
    data sender or data receiver, is handling output vertical tab character
    considerations, neither party is required to handle vertical tab
    characters and neither party is prohibited from handling them; but
    it is appropriate if at least the data receiver handles vertical tab
    character considerations, albeit primitively.

4. Motivation for the Option

 Please refer to section 4 of the NAOL and of the NAOVTD Telnet option
 descriptions.

5. Description of the Option

 The data sender and the data receiver use the 8-bit value along with
 the DS and DR SB commands as follows:
    8 bit value   Meaning
    0             Command sender suggests that he alone will handle
                  vertical tab characters, for the connection.
    1 to 250      Command sender suggests that the other party alone
                  should handle tab characters, but suggests that a 
	    delay of the indicated value be used. The value is 
	    the number of character-times to wait or number of
            NULs to insert in the data stream before sending the 
	    next data character.
    251           Command sender suggests that the other party alone
                  handle vertical tabs, but suggests that each 
	    occurrence of the character be replaced by 
	    carriage-return/linefeed.
    252           Command sender suggests that the other party alone
                  handle vertical tabs, but suggests that they be discarded.
    253           Command sender suggests that the other party alone
                  should handle tab characters, but suggests that 
	    tabbing be simulated.
    254           Command sender suggests that the other party alone
                  should handle the output disposition but suggests 
	    waiting for a character to be transmitted (on the 
	    other simplex connection) before sending more data.
            Note that, due to the assynchrony of the two 
	    simplex connections, phase problems can occur with 
	    this option.
    255           Command sender suggests that the other party alone
                  should handle the output disposition and suggests 
	    nothing about how it should be done.
 The guiding rules are that:
    1. if neither data receiver nor data sender wants to handle the 
    output vertical tab characters, the data receiver must do it, and
    2. if both data receiver and data sender want to handle the output
    vertical tab characters, the data sender gets to do it.
 The reasoning for the former rule is that if neither want to do it, then
 the default in the NAOVTD option dominates.  If both want to do it, the
 sender, who is presumed to have special knowledge about the data, should
 be allowed to do it, taking into account any suggestions the receiver may
 make.  Simulation is defined as the replacement of the character by
 enough line-feeds (only) to advance the paper (or line-pointer) to the
 next vertical tab stop.  
 Note that delays, controlled by the data sender, must consist of NUL
 characters, inserted immediately after the line-feed character.  This is
 necessary due to the assynchrony of network transmissions.  As with all
 option negotiations, neither party should suggest a state already in
 effect except to refuse to negotiate; changes should be acknowledged; and
 once refused, an option should not be resuggested until "something
 changes" (e.g., another process starts).  At any time, either party can
 disable further negotiation by giving the appropriate WON'T NAOVTD or
 DON'T NAOVTD command.
/data/webs/external/dokuwiki/data/pages/rfc/rfc657.txt · Last modified: 1992/10/15 21:52 by 127.0.0.1

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