Telnet output formfeed disposition option

　　TELNET OUTPUT FORMFEED DISPOSITION OPTION

　　RFC655, NIC 31158 (Oct. 25, 1974)

　　D. Crocker (UCLA-NMC)

　　Online file: [ISI]NAOFFD.TXT

　　TELNET OUTPUT FORMFEED DISPOSITION OPTION

　　1. Command name and code

　　NAOFFD - 13

　　(Negotiate About Output Formfeed 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 NAOFFD

　　The data sender requests or agrees to negotiate about output　formfeed 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 formfeeds.

　　IAC DON'T NAOFFD

　　The data sender refuses to negotiate about output formfeed　disposition with the data receiver, or demands a return to　the unnegotiated default mode.

　　IAC WILL NAOFFD

　　The data receiver requests or agrees to negotiate about　output formfeed 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 ormfeeds.

　　IAC WON'T NAOFFD

　　The data receiver refuses to negotiate about output formfeed　disposition, or demands a return to the unnegotiated default　mode.

　　IAC SB NAOFFD DS <8-bit value> IAC SE

　　The data sender specifies, with the 8-bit value, which party　should handle formfeeds and what their disposition should be.

　　The code for DS is 1.

　　IAC SB NAOFFD DR <8-bit value> IAC SE

　　The data receiver specifies, with the 8-bit value, which　party should handle formfeeds and what their disposition　should be. The code for DR is 0.

　　3. Default

　　DON'T NAOFFD/WON'T NAOFFD

　　In the default absence of negotiations concerning which party, data sender or data receiver, is handling output formfeeds, neither party　is required to handle formfeeds and neither party is prohibited from handling them; but it is appropriate if at least the data receiver handles formfeed considerations, albeit primitively.

　　4. Motivation for the Option

　　Please refer to section 4 of the NAOL and of the NAOFFD 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 formfeeds, for the connection.

　　1 to 250 Command sender suggests that the other party alone should handle formfeeds, but suggests that 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 formfeeds, but suggests that each occurrence of the character be replaced by carriage-return/line-feed.

　　252 Command sender suggests that the other party alone handle formfeeds, but suggests that they be discarded.

　　253 Command sender suggests that the other party alone should handle formfeeds, but suggests that formfeeds be simulated.

　　254 Command sender suggests that the other party alone should handle output formfeeds 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 output formfeeds 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 formfeeds, the data receiver must do it, and

　　2) if both data receiver and data sender want to handle output　formfeeds, 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 NAOFFD 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 formfeed character by enough line-feeds (only)　to advance the paper (or line-pointer) to the top of the next page　(or to the top of the terminal screen). Note that delays,　controlled by the data sender, must consist of NUL characters　inserted immediately after the formfeed character. This is　necessary due to the assynchrony of network transmission. 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 NAOFFD or DON'T NAOFFD command.