RFC 653 (rfc653) - Page 1 of 1

Telnet output horizontal tabstops option

TELNET OUTPUT HORIZONTAL TABSTOPS OPTION
RFC 653, NIC 31156 (Oct. 25, 1974)
D. Crocker (UCLA-NMC)
Online file: [ISI]NAOHTS.TXT

               TELNET OUTPUT HORIZONTAL TABSTOPS OPTION

1. Command name and code
   NAOHTS 11 (Negotiate About Output Horizontal Tabstops)

2. Command meanings
   In the following, we are discussing a simplex connection, as described in 
   the NAOL and NAOP Telnet options.
      IAC DO NAOHTS 
         The data sender requests or agrees to negotiate about output 
         horizontal 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 
         horizontal tabstops.
      IAC DON'T NAOHTS 
         The data sender refuses to negotiate about output horizontal tabstops 
         with the data receiver, or demands a return to the unnegotiated 
         default mode.
      IAC WILL NAOHTS 
         The data receiver requests or agrees to negotiate about output 
         horizontal 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 horizontal tabstops.
      IAC WON'T NAOHTS 
         The data receiver refuses to negotiate about output horizontal 
         tabstops, or demands a return to the unnegotiated default mode. 
      IAC SB NAOHTS DS  ...  IAC SE
         The data sender specifies, with the 8-bit value(s), which party should
         handle output horizontal tabstop considerations and what the stops 
         should be.  The code for DS is 1.
      IAC SB NAOHTS DR  ...  IAC SE
         The data receiver specifies, with the 8-bit value(s), which party 
         should handle output horizontal tabstop considerations and what the 
         stops should be.  The code for DR is 0.

3. Default
   DON'T NAOHTS/WON'T NAOHTS.
      In the default absence of negotiations concerning which party, data 
      sender or data receiver, is handling output horizontal tabstops, neither 
      party is required to handle them and neither party is prohibited from 
      handling them; but it is appropriate if at least the data receiver 
      handles horizontal tabstops, albeit primitively.

4. Motivation for the Option
   Please refer to section 4 of the NAOL and of the NAOP 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 subcommands 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  
                   tabstops, for the connection.                      
      1 to 250     Command sender suggests that the other party alone 
                   should handle tabstop considerations, but suggests 
                   that the indicated value(s) be used. The value(s)  
                   are the column numbers, relative to the physical   
                   left side of the printer page or terminal screen,  
                   that are to be set.                                
      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 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 
      horizontal tabstops, the data receiver must do it, and
      (2) if both data receiver and data sender want to handle output 
      horizontal tabstops, the data sender gets to do it.
   The reasoning for the former rule is that if neither wants to do it, then 
   the default in the NAOHTS 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.
   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 NAOHTS or DON'T NAOHTS command.