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TELNET OUTPUT VERTICAL TABSTOPS OPTIONRFC 656, NIC 31159 (Oct. 25, 1974)"D. Crocker (UCLA-NMC)Online file: [ISI]<DCROCKER>NAOVTS.TXT                TELNET OUTPUT VERTICAL TABSTOPS OPTION1. Command name and code   NAOVTS 14      (Negotiate About Vertcial Tabstops)2. Command meanings   In the following, we are discussing a simplex connection, as described in   the NAOL and NAOP Telnet Options specifications.      IAC DO NAOVTS         The data sender requests or agrees to negotiate about output         vertical tabstops 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 tabstop considerations.      IAC DON'T NAOVTS         The data sender refuses to negotiate about output vertical tabstops         with the data receiver, or demands a return to the unnegotiated         default mode.      IAC WILL NAOVTS         The data receiver requests or agrees to negotiate about output         vertical tabstops 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 tabstop         considerations.      IAC WON'T NAOVTS         The data receiver refuses to negotiate about output vertical         tabstops, or demands a return to the unnegotiated default mode.      IAC SB NAOVTS DS <8-bit value> ... <8-bit value> IAC SE         The data sender specifies, with the 8-bit value(s), which party         should handle output vertical tabstop considerations and what the         stops should be.  The code for DS is 1.      IAC SB NAOVTS DR <8-bit value> ... <8-bit value> IAC SE         The data receiver specifies, with the 8-bit value(s), which party         should handle output vertical tabstop considerations and what the         stops should be.  The code for DR is 0.3. Default   DON'T NAOVTS/WON'T NAOVTS.      In the default absence of negotiations concerning which party, data      sender or data receiver, is handling output vertical tabstop      considerations, neither party is required to handle vertical tabstops      and neither party is prohibited from handling them; but it is      appropriate if at least the data receiver handles vertical tabstop      considerations, albeit primitively.4. Motivation for the Option   Please refer tosection 4 of the NAOL and of the NAOVTS Telnet option   descriptions.

5. Description of the Option   The data sender and the data receiver use the 8-bit value(s) along with   the DS and DR SB commands as follows (multiple 8-bit values are allowed   only if each is greater than zero and less than 251):      8-bit value                      Meaning      0            Command sender suggests that he alone will handle                   the vertical tabstops, for the connection.      1 to 250     Command sender suggests that the other party alone                   should handle the stops, but suggests that the                   indicated value(s) be used.  Each value is the line                   number, relative to the top of the printer page or                   terminal screen, that is to be set as a vertical                   tabstop.      251 to 254   Not allowed, in order to be compatible with                   related Telnet options.      255          Command sender suggests that the other party alone                   should handle output vertical tabstops 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 output      vertical tabstops, the data receiver must do it, and      2) if both data receiver and data sender want to handle output vertical      tabstops, the data sender gets to do it.The reasoning for the former rule is that if neither wants to do it, thenthe default in the NAOVTS option dominates.  If both want to do it, thesender, who is presumed to have special knowledge about the data, should beallowed to do it, taking into account any suggestions the receiver may make.This is necessary due to the assynchrony of network transmissions.As with all option negotiations, neither party should suggest a statealready in effect except to refuse to negotiate; changes should beacknowledged; 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 theappropriate WON'T NAOVTS or DON'T NAOVTS command.