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rfc:rfc726
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
   Network Working Group             Jon Postel & Dave Crocker
   Request for Comments: 726            SRI-ARC      UC Irvine
   NIC: 39237                                     8 March 1977
   
   
     Remote Controlled Transmssion and Echoing Telnet Option
                                                                     1
   1.  Command name and code:                                        2
     RCTE 7                                                         2a
   2.  Command meanings:                                             3
     IAC WILL RCTE                                                  3a
       The sender of this command REQUESTS or AGREES to use
       the RCTE option, and will send instructions for
       controlling the other side's terminal printer.              3a1
     IAC WON'T RCTE                                                 3b
       The sender of this option REFUSES to send instructions
       for controlling the other side's terminal printer.          3b1
     IAC DO RCTE                                                    3c
       The sender REQUEST or AGREES to have the other side
       (sender of WILL RCTE) issue commands which will control
       his (sender of the DO) output to the terminal printer.      3c1
     IAC DON'T RCTE                                                 3d
       The sender of this command REFUSES to allow the other
       side to control his (sender of DON'T) terminal printer.     3d1
     IAC SB RCTE <cmd> [BC1 BC2] [TC1 TC2] IAC SE                   3e
       where:                                                      3e1
         <cmd> is one 8-bit byte having the following flags
         (bits are counted from the right):                       3e1a
                                                              [page 1]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
         Bit  Meaning                                             3e1b
          0   0 = Ignore all other bits in this byte and
                  repeat the last <cmd> that was sent. Equals
                  a 'continue what you have been doing'.
              1 = Perform actions as indicated by other bits
                  in this byte.                                   3e1c
          1   0 = Print (echo) break character
              1 = Skip (don't echo) break character               3e1d
          2   0 = Print (echo) text up to break character
              1 = Skip (don't echo) text up to break character    3e1e
          3   0 = Continue using same classes of break
                  characters.
              1 = The two 8-bit bytes following this byte
                  contain flags for the new break classes.        3e1f
          4   0 = Continue using same classes of transmit
                  characters.
              1 = Reset transmit classes according to the two
                  bytes following 1) the break classes bytes,
                  if the break classes are also being reset,
                  or 2) this byte, if the break classes are
                  NOT also being reset.                           3e1g
         Value (decimal) of the <cmd> byte and its meaning:       3e1h
         0 = Continue what you have been doing                    3e1i
         Even numbers greater than zero (i.e. numbers with the
         right most bit off) are in error and should be
         interpreted as equal to zero. When the <cmd> is an
         even number greater than zero, classes bytes TC1 &
         TC2 and/or BC1 & BC2 must not be sent.                   3e1j
         1 = Print (echo) up to AND INCLUDING break character     3e1k
         3 = Print up to break character and SKIP (don't echo)
             break character                                      3e1l
         5 = Skip text (don't echo) up to break character, but
             PRINT break character                                3e1m
         7 = Skip up to and including break character             3e1n
         Add one of the previous non-zero values to one of the
         following values, to get the total decimal value for
                                                              [page 2]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
         the byte (Note that classes may not be reset without
         also resetting the printing action; so an odd number
         is guaranteed):                                          3e1o
         8 = Set break classes (using the next two bytes [BC1
             BC2])                                                3e1p
         16 = Set transmission classes (using the next two
             bytes [TC1 TC2])                                     3e1q
         24 = Set break classes (using the next two bytes [BC1
             BC2]) and the transmission classes (using the two
             bytes after that [TC1 TC2]).                         3e1r
       Sub-commands (IAC SB RCTE...) are only sent by the
       controlling host and, in addition to other functions,
       functionally replace the Go-Ahead (IAC GA) Telnet
       feature. RCTE also functionally replaces the Echo (IAC
       ECHO) Telnet option. That is the Suppress Go-Ahead
       option should be in force and the Echo option should
       not be in force while the RCTE option is in use. The
       echo mode on terminating use of the RCTE option should
       be the default state, that is DON'T ECHO, WON'T ECHO.       3e2
       Classes for break and transmission (the right-most bit
       of the second byte (TC2 or BC2) represents class 1; the
       left-most bit of the first byte (TC1 or BC1) represents
       the currently undefined class 16:                           3e3
         1: Upper-Case Letter (A-Z)                               3e3a
         2: Lower-case Letters (a-z)                              3e3b
         3: Numbers (0-9)                                         3e3c
         4: Format Effectors (<BS> <CR> <LF> <FF> <HT> <VT>)      3e3d
           The sequence <cr><lf> counts as one character when
              processed as the Telnet end of line, and is a
              single break character when class 4 is set. The
              sequence <cr><nul> counts as one character and
              is a break character if and only if <cr> is a
              break character (i.e. class 4 is set).
         5: Non-format Effector Control Characters including
            <DEL> and <ESC>                                       3e3e
         6: . , ; : ? !                                           3e3f
                                                              [page 3]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
         7: { [ ( < > ) ] }                                       3e3g
         8: ' "  / \ % @ $ & # + - * = ^ _ | ~                    3e3h
         9: <Space>                                               3e3i
         And Telnet commands (IAC . . .) sent by the user are
         always to have the effect of a break character. That
         is, every instance of an IAC is to be treated as a
         break character, except the sequence IAC IAC.            3e3j
       The representation to be displayed when printing is
       called for is the obvious one for the visible
       characters (classes 1, 2, 3, 6, 7, and 8). Space (class
       9) is represented by a blank space. The format
       effectors (class 4) by their format effect. The
       non-format effector controls (class 5) print nothing
       (no space).                                                 3e4
       Initially no break classes or transmission classes are
       in effect.                                                  3e5
       Please note that if all the bits are set in a Telnet
       subcommand argument byte such as TC2 or BC2 then that
       byte must be preceeded by an <IAC> flag byte. This is
       the common convention of doubling the escape character
       to use its value as data.                                   3e6
       Sub-commands (IAC SB RCTE...) are refered to as "break
       reset commands".                                            3e7
   3.  Default:                                                      4
     WON'T RCTE -- DON'T RCTE                                       4a
       Neither host asserts special control over the other
       host's terminal printer.                                    4a1
   4.  Motivation for the option:                                    5
     RFC's 1, 5 and 51 discuss Network and process efficiency
     and smoothness.                                                5a
     RFC 357, by John Davidson, introduces the problem of
     echoing delay that occurs when a remote user accesses a
     full-duplex host, thru a satellite link. In order to save
     the many thousands of miles of transit time for each
     echoed character, while still permitting full server
     responsiveness and clean terminal output, an echo control
                                                              [page 4]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
     similar to that used by some time-sharing systems is
     suggested for the entire Network.                              5b
       In effect, the option described in this document
       involves making a using host carefully regulate the
       local terminal printer according to explicit
       instructions from the remote (serving) host.                5b1
     An important additional issue is efficient Network
     transmission. Implementation of the Davidson Echoing
     Scheme will eliminate almost all server-to-user echoing.       5c
       The option described in this document also requests
       using hosts to buffer a terminal's input to the serving
       host until it forms a useful unit (with "useful unit"
       delimited by break or transmission characters as
       described below). Therefore, fewer messages are sent on
       the user-to-server path.                                    5c1
     N.B.:  This option is only intended for use with
     full-duplex hosts. The Go-Ahead Telnet feature is
     completely adequate for half-duplex server hosts. Also,
     RCTE should be used in place of the ECHO Telnet option.
     That is the Suppress Go-Ahead option should be in force
     and the Echo option should not be in force while the RCTE
     option is in use.                                              5d
                                                              [page 5]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
   5.  Explicit description of control mechanism:                    6
     User Terminal Printing Action & Control Procedure              6a
       Negotiate the use of the RCTE option. Once the option
       is in force the user Telnet follows the following
       procedure.                                                  6a1
       1) Read an item from the network.                           6a2
         If the item is data, then print it and go to 1.          6a2a
         If the item is a command, then set the classes and go
         to 2.                                                    6a2b
       2) If the terminal input buffer is empty, then go to 3,
       else go to 4.                                               6a3
       3) Wait for an item to appear either from the terminal
       or from the network.                                        6a4
         If an item appears from the terminal, then go to 4.      6a4a
         If a data item appears from the network, then print
         it and go to 3.                                          6a4b
         If a command appears from the network, then an error
         has occured.                                             6a4c
       4) Read an item from the terminal input buffer.             6a5
         If the item is not a break, then print/skip it and go
         to 2.                                                    6a5a
         If the item is a break, then print/skip it and go to
         1.                                                       6a5b
       Note:  Output from the server host may occur at any
       time, such "spontaneous output" is printed in step 3.       6a6
                                                              [page 6]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
     Explanation:                                                   6b
       Both Hosts agree to use the RCTE option. After that,
       the using host (IAC DO RCTE) merely acts upon the
       controlling (serving) host's commands and does not
       issue any RCTE commands unless and until it (using
       host) decides to stop allowing use of the option (by
       sending IAC DON'T RCTE).                                    6b1
       1)  The using host is synchronized with the server by
       initially and when ever it returns to step 1 suspending
       terminal echo printing until it receives a command from
       the server.                                                 6b2
       The server may send either output to the terminal
       printer or a command, and usually sends a both.             6b3
       The server may send output to the terminal printer
       either in response to user input or spontaneously. In
       the former case, the output is processed in step 1. In
       the latter case, the output is processed in step 3.         6b4
       Server sends an RCTE command. The command may redefine
       break and transmission classes, action to be performed
       on break characters, and action to be performed on
       text. Each of these independent functions is controlled
       by separate bits in the <cmd> byte.                         6b5
         A transmission character is one which RECOMMENDS that
         the using host transmit all text accumulated up to
         and including its occurrence. (For network
         efficiency, using hosts are DISCOURAGED (but not
         prohibited) from sending before the occurrence of a
         transmission character, as defined at the moment the
         character is typed).                                     6b5a
           If the transmission classes bit (bit 4) is on, the
           two bytes following the two break classes bytes (or
           immediately following the <cmd> byte, if the break
           classes bit is not on) will indicate what classes
           are to be enabled.
           If the bit is OFF, the transmission classes remain
           unchanged. When the RCTE option is first initiated,
           NO CLASSES are in effect. That is, no character
           will be considered a transmission character. (As if
           both TC1 and TC2 are zero.)
         A break character REQUIRES that the using host
                                                              [page 7]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
         transmit all text accumulated up to and including its
         occurrence and also causes the using host to stop its
         print/discard action upon the user's input text,
         until directed to do otherwise by another IAC SB RCTE
         <cmd> IAC SE command from the serving host. Break
         characters therefore define printing units. "Break
         character" as used in this document does NOT mean
         Telnet Break character.                                  6b5b
           If the break classes bit (bit 3) is on, the two
           bytes following <cmd> will indicate what classes
           are to be enabled. There are currently nine (9)
           classes defined, with room for expansion.
           If the bit is OFF, the break classes remain
           unchanged. When the RCTE option is initiated, NO
           CLASSES are to be in effect. That is, no
           transmission will take place in the user to server
           direction until the first break reset command is
           received by the user from the server.
         The list of character classes, used to define break
         and transmission classes are listed at the end of
         this document, in the Tables Section.                    6b5c
         Because break characters are special, the
         print/discard action that should be performed upon
         them is not always the same as should be performed
         upon the rest of the input text.                         6b5d
           For example, while typing a filename to TENEX, I
           want the text of the filename to be printed
           (echoed); but I do not want the <escape> (if I use
           the name completion feature) to be printed.
           If bit 1 is ON the break character is NOT to be
           printed.
         A separate bit (bit 2) signals whether or not the
         text itself should be printed (echoed) to the
         terminal. If bit 2 = 0, then the text IS to be
         printed.                                                 6b5e
         Yet another bit (bit 0 - right-most bit) signals
         whether or not any of the other bits of the command
         should be checked. If this bit is OFF, then the
         command should be interpreted to mean "continue
         whatever echoing strategy you have been following,
         using the same break and transmission classes."          6b5f
                                                              [page 8]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
       2)  The user Telnet now checks the terminal input
       buffer, if it contains data it is processed in step 4,
       otherwise the user Telnet waits in step 3 for further
       developments.                                               6b6
       3)  The user Telnet waits until either the human user
       enters some data in which case Telnet proceeeds to step
       4, or an item is received from the network. If the item
       from the network is data it is spontaneous output and
       is printed, Telnet then continues to wait. If the item
       from the network is a command then an error has
       occured. In this case the user Telnet may attempt to
       resynchronize the use of RCTE as indicated below.           6b7
       4)  Items from the terminal are processed with printing
       controlled by the settings of the latest break reset
       command. When a break character is processed, the cycle
       of control is complete and action re-commences at step
       1.                                                          6b8
       Input from the terminal is (hopefully) buffered into
       units ending with a transmission or break character;
       and echoing of input text is suspended after the
       occurrence of a break character and until receipt of a
       break reset command from the serving host. The most
       recent break reset command determines the break
       actions.                                                    6b9
       In summary, what is required is that for every break
       character sent in the user to server direction there be
       a break reset command sent in the server to user
       direction. The user host initially has no knowledge of
       which characters are break characters and so starts in
       a state that assumes that there are no break characters
       and also that no echoing is to be provided. The server
       host is expected to send a break reset command to
       establish the break classes and the echoing mode before
       it receives any data from the user.                        6b10
     Synchronization and Resynchronization:                         6c
       The serving and using hosts must carefully synchronize
       break reset commands with the transmission of break
       characters. Except at the beginning of an interaction,
       the serving host may only send a break reset command in
       response to the Using host's having sent a break
       character as defined at that time. This should
       establish a one-to-one correspondence between them.  (A
       <cmd> value of zero, in this context, is interpreted as
                                                              [page 9]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
       a break classes reset to the same class(es) as before.)
       The break reset command may be preceded by terminal
       output.                                                     6c1
       The re-synchronization of the break characters and the
       break reset commands is done via the exchange of the
       Telnet signal Abort Output (AO) in the server to user
       direction and the SYNCH in the user to server
       direction.                                                  6c2
       Suppose the server wants to resynchronize the break
       characters and the break reset commands.                    6c3
         a.  The server should be sure all output to the
         terminal has been printed by using, for example, the
         Timing Mark Option.                                      6c3a
         b.  The server sends the AO signal.                      6c3b
         c.  The user receives the AO signal. The user flushes
         all user to server data wheather it has been echoed
         or not. The user sends a SYNCH to the server. [The
         SYNCH consists of the Telnet Data Mark (DM) and the
         host-to-host interrupt (INS).] The user now enters
         the initial state at step 1.                             6c3c
         d.  The server receives the SYNCH and flushes any
         data preceeding the DM (as always). The server now
         sends a break reset command. (Actually the break
         reset command could be sent at any time following the
         AO.)                                                     6c3d
       Suppose the user wants to resynchronize the break
       characters and the break reset commands.                    6c4
         a.  The user should discard all user to server data
         wheather it has been echoed or not.                      6c4a
         b.  The user sends the AO signal. The user now enters
         the algorithm at step 1.                                 6c4b
         c.  The server receives the AO signal. The server
         discards all data buffered but not yet sent to the
         user. The server sends a SYNCH to the user. The
         server sends a break reset command to the user.          6c4c
                                                             [page 10]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
     Notes and Comments:                                            6d
       Even-numbered commands, greater than zero, are in
       error, since they will have the low-order bit off. The
       command should be interpreted as equal to zero, which
       means that any classes reset bytes ([TC1 TC2] [BC1
       BC2]) will be in error. (The IAC SE, at the end of the
       command, eliminates any parsing problems due to this
       error.)                                                     6d1
       Serving hosts will generally instruct using hosts not
       to echo break characters, even though it might be
       alright to echo most break characters. For example,
       <cr> is usually a safe character to echo but <esc> is
       not. TENEX Exec is willing to accept either, during
       filename specification. Therefore, the using host must
       be instructed not to echo any break characters.             6d2
         This is generally a tolerable problem, since the
         serving host has to send an RCTE command at this
         point, anyhow. Adding an echo for the break character
         to the message will not cause any extra network
         traffic.                                                 6d2a
       The RCTE Option entails a rather large overhead. In a
       true character-at-a-time situation, this overhead is
       not justified. But on the average, it should result in
       significant savings, both in network traffic and host
       wake-ups.                                                   6d3
       Buffering Problems and Transmission vs. Printing
       Constraints:                                                6d4
         There are NO mandatory transmission constraints. The
         using host is allowed to send a character a time,
         though this would be a waste of RCTE. The
         transmission classes commands are GUIDELINES, so
         deviating from them, as when the user's buffer gets
         full, is allowed.                                        6d4a
         Additionally, the using host may send a break class
         character, without knowing that it is one (as with
         type-ahead).                                             6d4b
           If the user implementation is clever it may send
           the user entered data to the server before it is
           actually needed. This type ahead data may contain
           break characters.
                                                             [page 11]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
           Assume that only space is a break character (that
           is the last break reset command specified print up
           to and including the break characters and set the
           break classes to class 9). Suppose the user had
           typed "abc<space>def<esc>ghi<cr>". The user side
           RCTE could send it all to the server, but it could
           print only "abc<space>", and would have to buffer
           "def<esc>ghi<cr>" at least until a break reset
           command was received from the server. That break
           reset command could change the break ckasses
           requiring rescanning the buffered string.
           For example suppose the break reset command set the
           break characters to class 5 and the action to print
           up to but not including the break character. The
           user RCTE could then print "def" and discard the
           <esc>, but whould have to continue to buffer the
           "ghi<cr>".
         The problem with buffering occurs when printing on
         the user's terminal must be suspended, after the user
         has typed a currently valid break character and until
         a break reset command is received from the serving
         host. During this time, the user may be typing
         merrily along. The text being typed may be SENT, but
         may not yet be PRINTED.                                  6d4c
         The more common problem of filling the transmission
         buffer, while awaiting a host to host allocate from
         the serving host, may also occur, but this problem is
         well known to implementors and in no way special to
         RCTE.                                                    6d4d
         In any case, when the buffer does fill and further
         text typed by the user will be lost, the user should
         be notified (perhaps by ringing the terminal bell).      6d4e
       Text should be buffered by the using host until the
       user types a character which belongs to the
       transmission class in force at the moment the character
       is typed.                                                   6d5
       Transmission class reset commands may be sent by the
       serving host at any time. If they are frequently sent
       separate from break class reset commands, it will
       probably be better to exit from RCTE and enter regular
       character at a time transmission.                           6d6
       It is not immediately clear what the using host should
                                                             [page 12]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
       do with currently buffered text, when a transmission
       classes reset command is received. The buffering is
       according to the previous transmission classes scheme.      6d7
         The using host clearly should not simply wait until a
         transmission character (according to the new scheme)
         is typed.                                                6d7a
         Either the buffered text should be rescanned, under
         the new scheme;                                          6d7b
         Or the buffered text should simply be sent as a
         group. This is the simpler approach, and probably
         quite adequate.                                          6d7c
       It is possible to define NO BREAK CHARACTERS except
       Telnet commands (IAC ...). This seems undesirable and
       should not be done.                                         6d8
         If this situation were to occur the using host should
         send a Telnet command to allow the server to know
         when he may reset the break classes, but the
         mechanism is awkward and this case should be avoided.    6d8a
   6.  Sample Interaction:                                           7
     "S:" is sent from serving (WILL RCTE) host to using host.
     "U:" is sent from using (DO RCTE) host to serving host.
     "T:" is entered by the terminal user.
     "P:" is printed on the terminal.
     
     Text surrounded by square brackets ([]) is commentary.
     Text surrounded by angle brackets (<>) is to be taken as
     a single unit. E.g., carriage return is <cr>, and the
     decimal value 27 is represented <27>.                          7a
     The following interaction shows a logon to a Tenex,
     initiation of the DED editor, insertion of some text and
     the return to the Exec level.                                  7b
       An attempt has been made to give some flavor of the
       asynchrony of network I/O and the user's terminal
       input. Many other possible combinations, using the same
       set of actions listed below, could be devised. The
       actual order of events will depend upon network and
       hosts' load and the user's typing speed.                    7b1
     We assume that the user's Telnet is also in an "insert
     linefeed" mode. That is, whenever the user types carriage
                                                             [page 13]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
     return <cr> the user Telnet sends both carriage return
     and linefeed <cr><lf> (the Telnet end of line signal).
     When space character occurs at the end of a line in the
     example description it is shown explicitly by <sp> to
     avoid confusion. Other uses of the space character are
     not so marked to avoid destroying the readability of the
     example.                                                       7c
     A Telnet connection has already been opened, but the
     TENEX prompt has not yet been issued. The hosts first
     discuss using the RCTE option:                                 7d
       S: <IAC><WILL><RCTE>                                        7d1
       U: <IAC><DO><RCTE>                                          7d2
       S: TENEX 1.31.18, TENEX EXEC 1.50.2<cr><lf>@
          <IAC><SB><RCTE><11><1><24><IAC><SE>                      7d3
         [Print the herald and echo input text up to a break
         character, but do not echo the break character.
         Classes 4 (Format Effectors), 5 (Non-format Effector
         Controls and <DEL>), and 9 (<sp>) act as break
         characters.]                                             7d3a
       P: TENEX 1.31.18, TENEX EXEC 1.50.2<cr><lf>@                7d4
       T: LOGIN ARPA<cr>                                           7d5
       P: LOGIN                                                    7d6
       U: LOGIN<sp>                                                7d7
       U: ARPA<cr><lf>                                             7d8
       S: <sp><IAC><SB><RCTE><0><IAC>SE>                           7d9
       P: <sp>ARPA                                                7d10
       S: <cr><lf>(PASSWORD): <IAC><SB><RCTE><7><IAC><SE>         7d11
       P: <cr><lf>(PASSWORD):<sp>                                 7d12
       T: WASHINGTON 1000<cr>                                     7d13
         [The password "WASHINGTON" is not echoed. Printing of
         "1000<cr>" is withheld]                                 7d13a
       U: WASHINGTON<sp>                                          7d14
                                                             [page 14]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
       U: 1000<cr><lf>                                            7d15
       S: <sp><IAC><SB><RCTE><3><IAC><SE>                         7d16
       S: <cr><lf>JOB 17 ON TTY41 7-JUN-73 14:13<cr><lf>@
          <IAC><SB><RCTE><0><IAC><SE>                             7d17
       P: <sp>1000                                                7d18
         [Printing is slow at this point; so the account
         number is not printed as soon as the server's command
         for it is received.]                                    7d18a
       P: <cr><lf>JOB 17 ON TTY41 7-JUN-73 14:13<cr><lf>@         7d19
       T: DED<esc><cr>                                            7d20
       P: DED                                                     7d21
       U: DED<esc>                                                7d22
       S: .SAV;1<IAC><SB><RCTE><0><IAC><SE>                       7d23
       P: .SAV;1                                                  7d24
       U: <cr><lf>                                                7d25
       S: <cr><lf><lf>DED    3/14/73 DRO,KRK<cr><lf>:
          <IAC><SB><RCTE><15><1><IAC><255><IAC><SE>               7d26
         [The program is started and the DED prompt ":" is
         sent. At the command level, DED responds to every
         character. The server sets the break classes to all
         classes.]                                               7d26a
       P: <cr><lf><lf>DED    3/14/73 DRO,KRK<cr><lf>:             7d27
       T: IThis is a test line.<cr>This is another test
          line.<^Z>Q                                              7d28
         ["I" means Insert Text. The text follows, terminated
         by a Control-Z. The "Q" instructs DED to Quit.]         7d28a
       U: I                                                       7d29
       U: This is a test line.<cr><lf>                            7d30
       S: I<cr><lf>*<IAC><SB><RCTE><11><0><24><IAC><SE>           7d31
                                                             [page 15]
   NWG/RFC# 726                          JBP DHC 8-MAR-77 08:29  39237
   Remote Controlled Transmission & Echoing Telnet Option
         [DED prompts the user, during text input, with an
         asterisk at the beginning of every line. The server
         sets the break classes to classes 4 and 5, the format
         effectors and the non-format effector controls.]        7d31a
       P: I<cr><lf>*This is a test line.                          7d32
       S: <cr><lf>*<IAC><SB><RCTE><0><IAC><SE>                    7d33
       P: <cr><lf>*This is another test line.                     7d34
       U: This is another test line.<^Z>                          7d35
       U: Q                                                       7d36
         [Note that the "Q" will not immediately be printed on
         the terminal, since it must wait for authorization.]    7d36a
       S: ^Z<cr><lf>:<IAC><SB><RCTE><15><1><IAC><255><IAC><SE>    7d37
         [The returned "^Z" is two characters, not the ASCII
         Control-Z or <sub>.]                                    7d37a
       S: Q<cr><lf>@<IAC><SB><RCTE><11><1><24><IAC><SE>           7d38
       P: Q<cr><lf>@                                              7d39
       And the user is returned to the Exec level.                7d40
                                                             [page 16]
/data/webs/external/dokuwiki/data/pages/rfc/rfc726.txt · Last modified: 1992/10/15 21:54 by 127.0.0.1

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