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