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+Network Working Group                                          J. Winett
+Request for Comments: 452                                            JMW
+NIC: 14136                                               8 February 1973
+
+
+                       TELNET Command at Host LL
+
+   The attached writeup documents the use of the TELNET command at Host
+   LL for uses under the CP/CMS time-sharing system.  This command
+   provides for use in a HALF DUPLEX or FULL DUPLEX mode and can be used
+   with ASCII codes or with EBCDIC codes (i.e., transparent mode).  The
+   keyboard conventions allow for entering all ASCII codes using a
+   CONTROL character followed by another character for the codes not
+   present on an IBM 2741 terminal.  In addition a number of local
+   TELNET control commands have been defined which allows the mode of
+   operation to be changed, the redefinition of special characters, the
+   sending of TELNET control codes, as well as for obtaining input from
+   a file instead of from the terminal.  These later features provide
+   for a rudimentary file transfer facility.
+
+   This material has not been reviewed for public release and is
+   intended only for use with the ARPA network.  It should not be quoted
+   or cited in any publication not related to the ARPA network.
+
+   TELNET
+
+   Purpose:
+
+      To access another terminal oriented system on the ARPA network.
+
+   Format:
+
+      TELNET host <tag> RESUME     EBCDIC      HALFDUP
+                    1    OPEN       ASCII      FULLDUP
+
+      host - either the hexadecimal code for a foreign network service
+              site or a standard mnemonic for a foreign site.  See
+              Figure 1.
+
+      tag - the identifier for the local connections to the network.
+              The tag is used together with the address of the virtual
+              machine descriptor table (UTABLE) to form local socket
+              numbers which are used in the network protocol.
+
+      RESUME - used to reactivate communications with a foreign site
+              after having previously left the TELNET command leaving
+              the connections open.
+
+
+
+
+Winett                                                          [Page 1]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+      EBCDIC - to communicate with EBCDIC codes.  The default is network
+              ASCII.
+
+      HALFDUP - to operate under a half duplex protocol, i.e. with a
+              locked keyboard.
+
+              The EBCDIC HALFDUP the protocol assumes that the TELNET
+              break code (circle C) will be received to indicate when
+              the keyboard should be locked for input.
+
+              In ASCII HALFDUP the keyboard will lock after a line of
+              input and will unlock after one or more lines have been
+              received for output.  An external interrupt will also
+              unlock a locked keyboard.
+
+              The default is full duplex where the keyboard is always
+              unlocked for input.  A null line is required to
+              temporarily lock the keyboard in order to receive output.
+
+   Usage:
+
+      A number of hosts on the ARPA network provide TELNET service.  A
+      Network Virtual Terminal (NVT) has been specified so that using
+      sites can write one TELNET program which maps a local terminal
+      into the NVT to access any serving site on the network.  Once
+      communication has been established between a using site and a
+      serving site, keyed input is sent to the serving system and output
+      from the serving site, when received, is typed on the local
+      terminal.
+
+      The NVT protocol requires that the keyboard be capable of entering
+      all of the 128 ASCII codes together with a number of the TELNET
+      control codes.  To support an NVT with an IBM 2741 terminal, it is
+      necessary to adapt a control convention for entering codes which
+      are not associated with single keys on the keyboard.  In addition,
+      since CP/CMS processes input from a 2741 on a line at a time
+      terminated with a newline, a means must be establish for entering
+      a sequence of characters for transmission which is not terminated
+      with a newline code.
+
+      When TELNET is initiated the message
+
+                           ENTER CONTROL CHARACTER
+
+      is typed.  A non-blank character should then be entered which
+      defines the character which, in combination with another
+      character, will be used to enter codes not associated with single
+
+
+
+
+Winett                                                          [Page 2]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+      keys.  The control character is also used for other special
+      control functions as described below.
+
+   Codes:
+
+      The NVT usually requires that characters be transmitted in an
+      eight bit ASCII code.  Since the TELNET command is written to
+      process EBCDIC codes ASCII codes received are translated into
+      ASCII before being sent to a serving site.  Figure 2 gives the
+      complete definition of EBCDIC indicating the EBCDIC controls and
+      EBCDIC graphics.  Figure 3 gives the codes for the ASCII controls
+      and graphics.  The complete mapping between 8-bit EBCDIC codes and
+      8-bit network ASCII codes is shown in Figure 4.  The EBCDIC
+      newline code (NL) is mapped into the ASCII codes for the pair of
+      characters CR-IF.
+
+      The following ASCII/EBCDIC mapping is used for the non-EBCDIC
+      graphics:
+
+                        ASCII   EBCDIC
+
+                   TILDE (7E) = (A1) NOT
+                     BAR (7C) = (6A) OR
+              BACK SLASH (5C) = (EO)
+                   CARAT (5E) = (71)
+                   GRAVE (6O) = (79)
+              LEFT BRACE (7B) = (8B)
+             RIGHT BRACE (7D) = (9B)
+            LEFT BRACKET (5B) = (AD)
+           RIGHT BRACKET (5D) = (BD)
+
+      The ASCII control DC3 (X' 13') maps to the EBCDIC control TM
+      (X'13').  The ASCII control NUL (X' oo') is sent to the terminal
+      as the EBCDIC code for NULL (X' oo') and is not mapped into an
+      IDLE (X'17').
+
+      The TELNET control hide-your-input is mapped into the EBCDIC code
+      for bypass (print suppress) and the TELNET control noecho is
+      mapped into the EBCDIC code for restore (print restore).  If the
+      TELNET control for echo is received, a message is printed and it
+      is mapped into an IDLE.  Similarly, if the TELNET control for
+      break is received, a message is printed and it is mapped into an
+      IDLE unless operation is in EBCDIC HALFDUP mode in which case the
+      break is used to indicate that any received characters should be
+      printed and the keyboard unlocked for input.  If a data mark or an
+      interrupt is received, no action is taken except to print a
+      message to notify the user of this occurrence.
+
+
+
+
+Winett                                                          [Page 3]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+   Input:
+
+      When the control character is entered, the following character is
+      mapped into a different code than that which it is normally mapped
+      into, except when the following character is a space or a
+      character not defined to have a meaning when preceded by the
+      control character.  Figure 5 gives the mapping of the characters
+      on a 2741 keyboard when preceded by a control character.  The
+      following 2741 keyboard characters do not have a different meaning
+      when preceded by the control character.
+
+      $ # * % &
+      + - = _
+      . , : ;
+      ! | ? (cent sign)
+      SPACE
+      BACKSPACE
+      TAB
+
+      When a character is mapped into its control code, the control
+      character is mapped into the code for IDLE.  If the control
+      character is entered as the last character before the newline key
+      is entered, the sequence of characters entered is transmitted
+      without the newline code.  That is, the newline code is not
+      transmitted when it is preceded by the control character.
+
+      When the 2741 keyboard is unlocked for input, characters received
+      cannot be typed until the keyboard is locked again.  After a line
+      is entered, received characters can then be typed.  When operating
+      in full duplex or ASCII half duplex, a null line entered will
+      allow received characters to be typed but will not cause the new
+      line code to be transmitted.  To cause a null line, i.e., just the
+      new line code to be transmitted, the control character should be
+      entered as the only character in the input line.  In EBCDIC
+      HALFDUP a null line entered will cause a null line to be
+      transmitted.
+
+   Output:
+
+      ASCII output received from the NVT is converted into EBCDIC with
+      the sequences CR-LF converted into IDLE-NL.  The EBCDIC characters
+      are then sent to the terminal.  Note that not all 128 ASCII codes
+      when converted to EBCDIC will print on a 2741.  Of the 95 ASCII
+      graphics and the 8 ASCII controls which are defined for the NVT
+      printer, the following are not visible or audible:
+
+
+
+
+
+
+Winett                                                          [Page 4]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+            CARAT
+            GRAVE
+            BACK SLASH
+            LEFT BRACE
+            RIGHT BRACE
+            LEFT BRACKET
+            RIGHT BRACKET
+            ASCII CONTROL BELL (BEL)
+            ASCII CONTROL VERTICAL TAB (HT)
+            ASCII CONTROL FORM FEED (FF)
+            ASCII CONTROL CARRIAGE RETURN (CR)
+
+      Figure 6 shows how the EBCDIC codes from X' 40' through X' FF'
+      will appear on a 2741 terminal.  Figure 7 shows how the EBCDIC
+      codes will appear when printed with a PN train on the offline
+      printer and Figure 8 shows how these codes appear when printed
+      with a TN train.
+
+   Controls:
+
+      If the first character in an input line is the control character
+      and the next character is a space, the rest of the line is
+      interpreted as a TELNET control command.  A control command
+      consists of a control word and parameters separated by spaces.
+      Controls are defined which permit TELNET controls to be
+      transmitted to the serving site, allow input to come from a file
+      or output to go to a file, allow CMS functions or transient
+      commands to be issued, redefine the control character or TELNET
+      mode, close connections or leave the TELNET command with
+      connections still open, as well as controls to support a reader,
+      punch, and printer with RJS operation.  The controls are described
+      below.
+
+   CONTROL x
+
+      Where x is the new control character
+
+   CLOSE
+
+      To close all connections and quit
+
+   QUIT
+
+      To leave TELNET
+
+   EBCDIC
+
+      To go into transparent mode, i.e., no translation
+
+
+
+Winett                                                          [Page 5]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+   ASCII
+
+      To translate input and output to network ASCII
+
+   Break
+
+      To send the TELNET break code
+
+   SYNC
+
+      To send the TELNET data mark code and an interrupt
+
+   AATN
+
+      To send a TELNET break and a SYNC
+
+   HIDE-YOUR-INPUT
+
+      To send the TELNET hide you input code
+
+   NOECHO
+
+      To send the TELNET noecho code
+
+   ECHO
+
+      To send the TELNET echo code
+
+   CMS command arg1...argN
+
+      To issue CMS core resident function or transient command.
+
+   INPUT fn ft
+         *  TERMIN
+         *  *
+
+      To get input from a file If fn is defaulted, input is reset to
+      come from the terminal.  If fn is * file input resumes after the
+      last line read.  After an EOF, the next line read will be the
+      first line of the file.
+
+      An external interrupt while input is coming from a file will cause
+      the line number of the next line to be read from the file to be
+      typed and input to be reset to come from the terminal.
+
+
+
+
+
+
+
+Winett                                                          [Page 6]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+   OUTPUT fn OFF TERM    INPUT    INOUT
+          *  ON  NOTERM  NOINPUT  OUTPUT
+
+      To write output to the file "fn TERMOUT".  If fn is defaulted,
+      output is reset to go to the terminal.  If fn is *, file OUTPUT is
+      resumed with the same options as were last used.
+
+   For Output to the Terminal:
+
+      If the last character is a CR, a line with just the control
+      character is typed on the next line (with a NL)
+
+      If the last character is not a NL or a CR, the line is typed
+      without a NL (i.e., with TYPE).
+
+   For Output to a File:
+
+      If just a NL is in the line, just the control character is sent to
+      the file.
+
+      If the last CHAR is not NL or CR, the control character is added
+      after the last character, except if 130 characters must be sent to
+      the file.
+
+      If the last CHAR is a CR, it is included in the file.
+
+      OFF causes all output to be discarded.
+
+      ON is the default, and causes output to the terminal.
+
+      TERM causes output to also go to the terminal.
+
+      NOTERM is the default, and causes output to go the file but not to
+      the terminal.
+
+      OUTPUT is the default and causes just terminal output to be put to
+      the file "FN termout".
+
+
+      INPUT causes both terminal input but not output to be put to the
+      output file.
+
+      NOINPUT is defaulted and causes input to not go to the file.
+
+   PURGE
+
+      To purge all output currently received by the NCP.
+      *****NOT YET IMPLEMENTED*****
+
+
+
+Winett                                                          [Page 7]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+   READER fn ft
+          * READER
+
+      To send a job to the RJS system at UCLA's CCN.
+
+      If fn and ft are defaulted, input will come from the card reader.
+
+   PRINTER fn ft
+           *  PRINTER
+
+   To receive printer output from the RJS system at UCLA's CCN.
+
+   To receive punch output from the RJS system at UCLA's CCN.
+
+   If fn and ft are defaulted, output goes to the printer.
+
+   PUNCH fn ft
+         *  PUNCH
+
+      If fn and ft are defaulted, output goes to the punch.
+
+   HOST      SITE      MACHINE   SYSTEM      HOST NUMBER
+                                           DEC   OCT   HEX
+
+   NMC       UCLA      SIGNA-7   SEX         1     1    01
+   ARC       SRI       PDP-10    NIC         2     2    02
+   UCSB      UCSB      360/75    OS/MVT      3     3    03
+   UTAH      UTAH      PDP-10    TENEX       4     4    04
+   MULTICS   MIT       H-645     MULTICS     6     6    06
+   SDC       SDC       370/155   ADEPT       8    10    08
+   HARV      HARVARD   PDP-10    4S72        9    11    09
+   LL        LL        360/67    CP/CMS     10    12    0A
+   CASE      CASE      PDP-10    10/50      13    15    0D
+   CMU       CMU       PDP-10    TOPS-10    14    16    0E
+   ILLIAC    AMES      360/67    TTS/360    16    18    10
+   AMES      AMES      B-6500    ?          15    17    0F
+   CCN       UCLA      360/91    OS/MVT     65   101    41
+   SRI       SRI-AI    PDP-10    TENEX      66   102    42
+   BBNA      BBN       PDP-10    TENEX      69   105    45
+   DMCG      MIT       PDP-10    ITS        70   106    46
+   RAND      RAND-RCC  PDP-10    TENEX      71   107    47
+   TX2       LL        TX-2      APEX       74   112    4A
+   BBNB      BBN       PDP-10    TENEX     133   205    85
+   MIATI     MIT       PDP-10    ITS       134   206    86
+
+                     Serving Hosts on the APRA Network
+                                 Figure 1
+
+
+
+
+Winett                                                          [Page 8]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+                       [[See Figure 2 in PDF file.]]
+          Extended Binary-Coded Decimal Interchange Code (EBCDIC)
+                                 FIGURE 2
+
+   and
+
+                       [[See Figure 3 in PDF file.]]
+          USA Standard Code for Information Interchange (USASCII)
+                                 FIGURE 3
+
+
+   ASCII    ASCII    ASCII    SYMBOLS    EBCDIC    EBCDIC
+   DEC      OCT      HEX                 HEX       DEC
+
+     0        0      (00)      NUL       (00)      00
+     1        1      (01)      SOH       (01)      01
+     2        2      (02)      STX       (02)      02
+     3        3      (03)      ETX       (03)      03
+     4        4      (04)      EOT       (37)      55
+     5        5      (05)      ENQ       (2D)      45
+     6        6      (06)      ACK       (2E)      46
+     7        7      (07)      BEL       (2F)      47
+     8       10      (08)      BS        (16)      22
+     9       11      (09)      HT        (05)      05
+    10       12      (0A)      LF        (25)      37
+    11       13      (0B)      VT        (0B)      11
+    12       14      (0C)      FF        (0C)      12
+    13       15      (0D)      CR        (0D)      13
+    14       16      (0E)      SO        (0E)      14
+    15       17      (0F)      SI        (0F)      15
+    16       20      (10)      DLE       (10)      16
+    17       21      (11)      DC1       (11)      17
+    18       22      (12)      DC2       (12)      18
+    19       23      (13)      DC3       (13)      19
+    20       24      (14)      DC4       (3C)      60
+    21       25      (15)      NAK       (3D)      61
+    22       26      (16)      SYN       (32)      50
+    23       27      (17)      ETB       (26)      38
+    24       30      (18)      CAN       (18)      24
+    25       31      (19)      EM        (19)      25
+    26       32      (1A)      SUB       (3F)      63
+    27       33      (1B)      CTL       (27)      39
+    28       34      (1C)      FS        (1C)      28
+    29       35      (1D)      GS        (1D)      29
+    30       36      (1E)      RS        (1E)      30
+    31       37      (1F)      US        (1F)      31
+    32       40      (20)      SP        (40)      64
+    33       41      (21)      !         (5A)      90
+
+
+
+Winett                                                          [Page 9]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+    34       42      (22)      "         (7F)     127
+    35       43      (23)      #         (7B)     123
+    36       44      (24)      $         (5B)      91
+    37       45      (25)      %         (6C)     108
+    38       46      (26)      &         (50)      80
+    39       47      (27)      '        (7D)     124
+    40       50      (28)      (         (4D)      77
+    41       51      (29)      )         (5D)      93
+    42       52      (2A)      *         (5C)      92
+    43       53      (2B)      +         (4E)      78
+    44       54      (2C)      ,         (6D)     109
+    45       55      (2D)      -         (60)      96
+    46       56      (2E)      .         (4B)      75
+    47       57      (2F)      /         (61)      97
+    48       60      (30)      0         (F0)     240
+    49       61      (31)      1         (F1)     241
+    50       62      (32)      2         (F2)     242
+    51       63      (33)      3         (F3)     243
+    52       64      (34)      4         (F4)     244
+    53       65      (35)      5         (F5)     245
+    54       66      (36)      6         (F6)     246
+    55       67      (37)      7         (F7)     247
+    56       70      (38)      8         (F8)     248
+    57       71      (39)      9         (F9)     249
+    58       72      (3A)      :         (7A)     122
+    59       73      (3B)      ;         (5E)      94
+    60       74      (3C)      <         (4C)      76
+    61       75      (3D)      =         (7E)     126
+    62       76      (3E)      >         (6E)     110
+    63       77      (3F)      ?         (6F)     111
+    64      100      (40)      @         (7C)     124
+    65      101      (41)      A         (C1)     193
+    66      102      (42)      B         (C2)     194
+    67      103      (43)      C         (C3)     195
+    68      104      (44)      D         (C4)     196
+    69      105      (45)      E         (C5)     197
+    70      106      (46)      F         (C6)     198
+    71      107      (47)      G         (C7)     199
+    72      110      (48)      H         (C8)     200
+    73      111      (49)      I         (C9)     201
+    74      112      (4A)      J         (D1)     209
+    75      113      (4B)      K         (D2)     210
+    76      114      (4C)      L         (D3)     211
+    77      115      (4D)      M         (D4)     212
+    78      116      (4E)      N         (D5)     213
+    79      117      (4F)      O         (D6)     214
+    80      120      (50)      P         (D7)     215
+    81      121      (51)      Q         (D8)     216
+
+
+
+Winett                                                         [Page 10]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+    82      122      (52)      R         (D9)     217
+    83      123      (53)      S         (E2)     226
+    84      124      (54)      T         (E3)     227
+    85      125      (55)      U         (E4)     228
+    86      126      (56)      V         (E5)     229
+    87      127      (57)      W         (E6)     230
+    88      130      (58)      8         (E7)     231
+    89      131      (59)      Y         (E8)     232
+    90      132      (5A)      Z         (E9)     233
+    91      133      (5B)      [         (AD)     173
+    92      134      (5C) (cent sign)    (4A)      74  (BACK-SLASH)
+    93      135      (5D)      ]         (BD)     189
+    94      136      (5E)                (71)     113  (CARAT)
+    95      137      (5F)      _         (6D)     109
+    96      140      (60)                (79)     121  (GRAVE)
+    97      141      (61)      a         (81)     129
+    98      142      (62)      b         (82)     130
+    99      143      (63)      c         (83)     131
+   100      144      (64)      d         (84)     132
+   101      145      (65)      e         (85)     133
+   102      146      (66)      f         (86)     134
+   103      147      (67)      g         (87)     135
+   104      150      (68)      h         (88)     136
+   105      151      (69)      i         (89)     137
+   106      152      (6A)      j         (91)     145
+   107      153      (6B)      k         (92)     146
+   108      154      (6C)      l         (93)     147
+   109      155      (6D)      m         (94)     148
+   110      156      (6E)      n         (95)     149
+   111      157      (6F)      o         (96)     150
+   112      160      (70)      p         (97)     151
+   113      161      (71)      q         (98)     152
+   114      162      (72)      r         (99)     153
+   115      163      (73)      s         (A2)     162
+   116      164      (74)      t         (A3)     163
+   117      165      (75)      u         (A4)     164
+   118      166      (76)      v         (A5)     165
+   119      167      (77)      w         (A6)     166
+   120      170      (78)      x         (A7)     167
+   121      171      (79)      y         (A8)     168
+   122      172      (7A)      z         (A9)     169
+   123      173      (7B)      {         (8B)     139
+   124      174      (7C)      |         (4F)      79  (BAR/OR)
+   125      175      (7D)      }         (9B)     155
+   126      176      (7E) (broken bar)   (5F)      95  (TILDE/NOT)
+   127      177      (7F)      DEL       (07)       7
+
+
+
+
+
+Winett                                                         [Page 11]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+   ASCII   ASCII   ASCII    TELNET         EBCDIC     EBCDIC
+   DEC     OCT     HEX     CONTROLS        HEX        DEC
+
+   128     100     (80)   DATA-MARK        (80)       128
+   129     101     (81)   BREAK            (38)        56
+   130     102     (82)   NOP              (17)        23  IDLE
+   131     103     (83)   NOECHO           (14)        20  RESTORE
+   132     104     (84)   ECHO             (23)        35
+   133     105     (85)   HIDE-YOUR INPUT  (24)        36  BYPASS
+
+                        ASCII/EBCDIC Code Mappings
+                                 FIGURE 4
+
+   EBCDIC                  EBCDIC ASCII
+
+   CENT    (4A) = ESC             (27)   (1B)
+
+   CTL <   (4C) = LEFT BRACKET    (AD)   (5B)
+   CTL >   (6E) = RIGHT BRACKET   (BD)   (5D)
+   CTL (   (4D) = LEFT BRACE      (8B)   (7B)
+   CTL )   (5D) = RIGHT BRACE     (9B)   (7D)
+   CTL /   (61) = BACK SLASH      (4A)   (5C)
+   CTL "   (7F) = CARAT           (71)   (5E)
+   CTL '  (7D) = GRAVE            (79)   (60)
+
+   CTL 6   (F6) = FS              (1C)   (1C)
+   CTL 7   (F7) = GS              (1D)   (1D)
+   CTL 8   (F8) = RS              (1E)   (1E)
+   CTL 9   (F9) = US              (1F)   (1F)
+   CTL _   (6D) = US              (1F)   (1F)
+
+   CTL (broken bar) (5F) = DEL             (07)   (7F)
+
+   CTL @   (7C) = NUL             (00)   (00)
+   CTL A   (C1) = SOH             (01)   (01)
+   CTL B   (C2) = STX             (02)   (02)
+   CTL C   (C3) = ETX             (03)   (03)
+   CTL D   (C4) = EOT             (37)   (04)
+   CTL E   (C5) = ENQ             (2D)   (05)
+   CTL F   (C6) = ACK             (2E)   (06)
+   CTL G   (C7) = BEL             (2F)   (07)
+   CTL H   (C8) = BS              (16)   (08)
+   CTL I   (C9) = HT              (05)   (09)
+   CTL J   (D1) = LF              (25)   (0A)
+   CTL K   (D2) = VT              (0B)   (0B)
+   CTL L   (D3) = FF              (0C)   (0C)
+   CTL M   (D4) = CR              (0D)   (0D)
+
+
+
+
+Winett                                                         [Page 12]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+   CTL N   (D5) = SO              (0E)   (0E)
+   CTL O   (D6) = SI              (0F)   (0F)
+
+   CTL P   (D7) = DLE             (10)   (10)
+   CTL Q   (D8) = DC1             (11)   (11)
+   CTL R   (D9) = DC2             (12)   (12)
+   CTL S   (E2) = DC3             (13)   (13)
+   CTL T   (E3) = DC4             (3C)   (14)
+   CTL U   (E4) = NAK             (3D)   (15)
+   CTL V   (E5) = SYN             (32)   (16)
+   CTL W   (E6) = ETB             (26)   (17)
+   CTL X   (E7) = CAN             (18)   (18)
+   CTL Y   (E8) = EM              (19)   (19)
+   CTL Z   (E9) = SUB             (3F)   (1A)
+
+        EBCDIC                   EBCDIC ASCII
+
+   CTL 1 (F1) = BREAK          (38)  (81) - CIRCLE C
+   CTL 2 (F2) = NOP            (17)  (82) - IDLE
+   CTL 3 (F3) = NO ECHO        (14)  (83) - RESTORE
+   CTL 4 (F4) = ECHO           (23)  (84)
+   CTL 5 (F5) = HIDE YOU INPUT (24)  (85) - BYPASS
+
+   DATA MARK (80) CANNOT BE ENTERED FROM THE KEYBOARD
+
+   THE FOLLOWING 2741 KEYBOARD CHARACTERS DO NOT
+   HAVE A MEANING AS A CONTROL:
+
+         $ # * % &
+         + - = _
+         . , :
+         ! | ? (cent sign)
+         SPACE
+         BACKSPACE
+         TAB
+
+                    Keyboard Control Character Mappings
+                           FIGURE 5 (CONTINUED)
+
+
+
+
+
+
+
+
+
+
+
+
+
+Winett                                                         [Page 13]
+
+RFC 452                TELNET Command at Host LL           February 1973
+
+
+   [[See Figure in PDF file.]]
+   Hex Code X'xy' for Characters on a 2741 Terminal
+
+   [[See Figure in PDF file.]]
+   Decimal Code D 'xxy" for Characters on a 2741 terminal
+
+   HT  X'05' = D'005' Horizontal Tab
+   LC  X'06' = D'006' Lower Case
+   RES X'14' = D'020' Print Restore
+   NL  X'15' = D'021' New Line
+   BS  X'16' = D'022' Back Space
+   IL  X'17' = D'023' Idle
+   BYP X'24' = D'036' Print Bypass
+   LF  X'25' = D'037' Line Feed
+   UC  X'36' = D'054' Upper Case
+
+   Hex Code X'xy' and Decimal Code D'xxy' for 2741 Control Codes
+
+   [[See Figure in PDF file.]]
+   Hex Code X'xy' for Characters on the PN train
+
+   [[See Figure in PDF file.]]
+   Decimal Code D'xxy' for characters on the PN train
+
+   [[See Figure in PDF file.]]
+   Hex Code X'xy' for Characters on th TN train
+
+   [[See Figure in PDF file.]]
+   Decimal Code D'xxy' for Characters on the TN train
+
+          [This RFC was put into machine readable form for entry]
+     [into the online RFC archives by Helene Morin, Via Genie,12/1999]
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Winett                                                         [Page 14]
+