D. Crocker (UCLA-NMC) RFC 658, NIC 31161 (Oct. 25, 1974) Online file: [ISI]<DCROCKER>NAOLFD.TXT
8-bit value Meaning 0 Command sender suggests that he alone will handle linefeeds, for the connection. 1 to 250 Command sender suggests that the other party alone should handle linefeeds, 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. (See qualifications, below.) 251 Not allowed, in order to be compatible with related Telnet options. 252 Command sender suggests that the other party alone handle linefeeds, but suggests that they be discarded. 253 Command sender suggests that the other party alone should handle linefeeds, but suggests that linefeeds be simulated. 254 Command sender suggests that the other party alone should handle output linefeeds but suggests waiting for a character to be transmitted (on the other simplex connection) before sending more data. (See qualifications, below.) 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 output linefeeds 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
linefeeds, the data receiver must do it, and
2) if both data receiver and data sender want to handle output linefeed disposition, 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 NAOLFD 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 linefeed character
by new-line (see following) and enough blanks to move the print head (or
line pointer) to the same lateral position it occupied just prior to
receiving the linefeed. To avoid infinite recursion, such simulation is
allowed only for linefeed characters that are not immediately preceded by
carriage-returns (that is, part of a Telnet new-line combination). It is
assumed that linefeed simulation will be necessary for printers that do
not have a separate linefeed (like the IBM 2741); in this case,
end-of-line character padding can be specified through NAOCRD. Any
padding (0 < <8-bit-value> < 251) of linefeed characters is to be done
for ALL linefeed characters.