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rfc:rfc183

Network Working Group J.M. Winett Request for Comments: 183 Lincoln Laboratory NIC: 7127 July 21, 1971

Categories: D.2, D.3 Related: 109, 110, 105, 158

            The EBCDIC Codes and Their Mapping to ASCII

Abstract

 The uniquely map the ASCII codes into corresponding EBCDIC codes in a
 consistent manner throughout the ARPA Network, this RFC describes and
 defines the IBM Standard Extended BCD Interchanged Code.

Introduction

 The IBM Corporate Systems Standard, Extended BCD Interchanged Code
 (EBCDIC) defines 8-bit graphic and control codes (See Figure 1).  The
 basic EBCDIC code consists of 54 controls (including space) and 88
 graphics.  This set is extended to include 10 special graphics and 1
 special control (EO).  These special graphics originate from the 7-
 bit hollerith code and include 6 ASCII graphics.  The EBCDIC code is
 further extended to include the publishing and printing graphics
 option which specifics 52 graphics.  Of these graphics, 32 appear on
 the IBM TN print chain.  Four of these graphics are duals with
 graphics not on the TN print chain, and one graphic (degree) is dual
 with a graphic in the special graphics set of the basic code (tilde).
 It is desirable to uniquely map the ASCII codes into corresponding
 EBCDIC codes in a consistent manner throughout the ARPA network.
 For each of the 34 ASCII controls (including space and delete) there
 is a corresponding BDCDIC control (assigning ASCII control DC3 to the
 EBCDIC code X'13').  For 85 of the 94 ASCII graphics, there is a
 corresponding graphic in the basic EBCDIC set.  Three different
 correspondences can be made for the other 9 ASCII graphics.

Winett [Page 1] RFC 183 EBCDIC Codes and Their Mapping to ASCII July 21, 1971

I. IBM Correspondence

 a) IBM recommends the following ASCII duals with the basic EBCDIC
    graphics.
         ASCII                   EBCDIC                  Code
         [                       [cent sign]             X'4A'
         ]                       !                       X'5A'
         !                       l                       X'4F'
         [carrot sign]           [upper right corner]    X'5F'
 Note that the EBCDIC graphic for exclamation point (!) is not chosen
 to correspond to the ASCII for exclamation point (!), though this
 would be a sensible choice, and thus another code must be used to
 represent this graphic.
 b) Special EBCDIC graphics would be used to represent the other ASCII
    graphics.
         Graphic                         Code
         l                               X'6A'
         l                               X'79'
         [diagonal slash]                X'A1'
         ~                               X'E0'
         [diagonal slash]                XC0'
         {                               XD0'
         }

II. Publishing Correspondence

 a) Associate the following special EBCDIC graphics with the
    corresponding ASCII graphics.
         Graphic                         Code
         [carrot]                        X'71'
         [                               X'AD'
         ]                               X'BD'
         {                               X'8B'
         }                               X'9B'
 The codes for open bracket and close bracket are chosen since these
 graphics appear on the TN print chain.  The codes for left brace and
 right brace are chosen rather than the codes in the special graphics
 set for opening brace and closing brace, respectively, since these
 graphics are similar and also appear on the TN print chain.

Winett [Page 2] RFC 183 EBCDIC Codes and Their Mapping to ASCII July 21, 1971

III. Graphical Correspondence

 a) Associate the following basic EBCDIC graphics with the indicated
    ASCII graphics because of their graphic similarity.
         |                       X'4F'           with |
                                                      |
         [upper right corner]    X'5F'           with ~
 b) Associate the basic EBCDIC graphic for cent with the ASCII graphic
    for reverse slash.
         [cent]          X'4A'           with [diagonal slash]
 This choice is made since the cent graphic is not an ASCII graphic
 and is the only graphic in the basic EBCDIC set which would not
 otherwise be associated with any ACII graphic.
 c) Associate the special EBCDIC graphic grave accent.
       `  X'79'
    with the corresponding ASCII graphic.
 d) Associate the following publishing EBCDIC graphics with the
 corresponding ASCII graphics.
         [carrot]        X'71'
         [               X'AD'
         ]               X'BD'
         {               X'8B'
         }               X'9B'
 The codes for open bracket and close bracket are chosen since these
 graphic appear on the TN print chain.  The codes for left brace and
 right brace are chosen rather than the codes in the special graphics
 set for opening brace and closing brace, respectively, since these
 graphics are similar and also appear on the TN print chain.
 Standards:
 In order that the mapping from ASCII into EBCDIC and vice versa could
 become standardized, I would appreciate comments on the above from
 each site whose operating system uses EBCDIC as the internal code.

Winett [Page 3] RFC 183 EBCDIC Codes and Their Mapping to ASCII July 21, 1971

 Telnet Codes:
 For those sites who may wish to provide our use TELNET services that
 communicate using an EBCDIC code, a standard code must be specified.
 The codes given in Figure 1 can form the basis for a standard.
 Specific codes must also be specified for the TELNET control codes.
 The following are suggested:
                                 Hex Code
         sync                    38
         break                   39
         NOP                     3A
         Return to ASCII         FF
         No echo                 14
         Echo                    23
         Hide input              24
 To eliminate using one code for two graphics, I propose that the TN
 graphics be associated with their corresponding code.  The graphic
 tilde (~) might be assigned to the code X'E1' rather than keeping the
 dual with the graphic for degree.  This would have no effect if the
 Graphical Correspondence were chosen for the EBCDIC to ASCII mapping
 with the code X'5F' for logical not associated with tilde.  The other
 graphics of the publishing and printing option (Double Acute,
 Inferior Hook, Macron, and Inferior Comma) which are not on the TN
 print chain but have the same codes as graphics on the TN print chain
 would not be considered to be part of the standard EBCDIC code.

Winett [Page 4] RFC 183 EBCDIC Codes and Their Mapping to ASCII July 21, 1971

EBCDIC Questionnaire

 1. For ASCII to EBCDIC mapping of the 9 special ASCII graphics do you
    prefer:
    a)   The IBM correspondence             _____________
    b)   The Publishing correspondence      _____________
    c)   The Graphical correspondence       _____________
    d)   Another correspondence (describe)  _____________
 2. Do you concur with the definition of the standard EBCDIC code,
    including TELNET control codes?
         YES __________  NO __________
    Comments:
    __________________________________________________________________
    __________________________________________________________________
    __________________________________________________________________
 3. Please list for your operating system:
    a)   graphics not included in the complete EBCDIC code.
    b)   Graphics given a different code.
    c)   Controls given one of the graphic codes.
    d)   Controls given one of the control codes but defined to be a
         different control
    e)   All the controls which have meaning with your operating
         system (i.e., for which special action is taken) and state
         the action.
 Reply from:     Name                    _________________
                 Telephone               _________________
                 Site                    _________________
                 Host Computer           _________________
 Send to:        Joel M. Winett
                 M.I.T. Lincoln Laboratory
                 Room C-151
                 Lexington, Mass. 02173
 Or call:        (617) 862-5500 ext. 7474
 Figure 1.  [Please view the PDF version of this RFC.]
 Figure 2.  [Please view the PDF version of this RFC.]

Winett [Page 5] RFC 183 EBCDIC Codes and Their Mapping to ASCII July 21, 1971

 Hex Code      Category      Control      Name
 00            CC            NUL          Null
 01            CC            SOH          Start of Heading
 02            CC            STX          Start of Text
 03            CC            ETX          End of Text
 04            DC            PF           Punch off
 05            FE            HT           Horizontal Tab
 06            GR            LC           Lower Case
 07            GR            DEL          Delete
 08            GR            GE           Graphic Escape
 09            FE            RLF          Reverse Line Feed
 0A            CC            SMM          Start of Manual Message
 0B            FE            VT           Vertical Tab
 0C            FE            FF           Form Feed
 0D            FE            CR           Carriage Return
 0E            GR            SO           Shift Out
 0F            GR            SI           Shift In
 10            CC            DLE          Data Line Escape
 11            DC            DC1          Device Control 1
 12            DC            DC2          Device Control 2
 13            DC            TM/DC3       Tape Mark/Device Control 3
 14            DC            RES          Restore
 15            FE            NL           New Line
 16            FE            BS           Backspace
 17            DC            IL           Idle
 18            GR            CAN          Cancel
 19            DC            EM           End of Medium
 1A            DC            CC           Cursor Control
 1B            CU            CUI          Customer Use 1
 1C            IS            IFS          Info. Field Separator
 1D            IS            IGS          Info. Group Separator
 1E            IS            IRS          Info. Record Separator
 1F            IS            IUS          Info. Unit Separator
 20            ED            DS           Digit Select
 21            ED            SOS          Start of Significance
 22            ED            FS           Field Separator
 23                                       (Reserved)
 24            DC            BYP          Bypass
 25            FE            LF           Line Feed
 26            CC            ETB          End of Text Block
 27            GR            ESC          Escape
 28                                       (Reserved)
 29                                       (Reserved)
 2A            DC            SM           Set Mode
 2B            CU            CU2          Customer Use 2
 2C                                       (Reserved)

Winett [Page 6] RFC 183 EBCDIC Codes and Their Mapping to ASCII July 21, 1971

 2D            CC            ENQ          Enquiry
 2E            CC            ACK          Acknowledge
 2F            DC            BEL          Bell
 30                                       (Reserved)
 31                                       (Reserved)
 32            CC            SYN          Synchronous Idle
 33                                       (Reversed)
 34            DC            PN           Punch On
 35            DC            RS           Reader Stop
 36            GR            UC           Upper Case
 37            CC            EOT          End of Transmission
 38                                       (Reserved)
 39                                       (Reserved)
 3A                                       (Reserved)
 3B            CU            CU3          Customer Use 3
 3C            DC            DC4          Device Control 4
 3D            CC            NAK          Negative Acknowledge
 3E                                       (Reserved)
 3F            GR            SUB          Substitute
                  Figure 3: EBCDIC Control Functions

Winett [Page 7] RFC 183 EBCDIC Codes and Their Mapping to ASCII July 21, 1971

 CC    ([illegible] Control). A functional character  [illegible] to
       control or facilitate transmission of introducing [illegible]
       communication networks.
 FB    (Format Bisector). A functional character which controls the
       layout of positioning or information in printing or display
       devices.
 IS    (Information Separator). A character which is used to separate
       and qualify information in a logical sense. There is a group of
       four such characters, which are to be used in a hierarchical
       order.
 DC    (Device Control). A functional character used for the control
       of ancillary devices associated with data processing of
       telecommunication systems, more especially switching devices
       "on" and "off".
 ED    (Edit and Mark). A control character used by the
       System/[illegible]...and Mark ([illegible]) instruction for the
       formatting of alphanumeric fields.
 GH    (Graphic Control). A control character indicating that the core
       combinations which follow are to be [illegible] in a particular
       code table, depending upon the particular control character.
 CU    (Customer Use). A character excluded from future assignment by
       IBM.  These "protected" codes are intended for use by customer
       systems so that their use will not conflict with a possible
       future IBM use.
                               Figure 4
                    Categories of Control Functions

Winett [Page 8] RFC 183 EBCDIC Codes and Their Mapping to ASCII July 21, 1971

    Hex Code             Graphic                 Name
 *   6A                  |                       Vertical Line
                         |
 *   79                  [diagonal slash]        Grave Accent
 *   A1                  ~                       Tilde
 *   C0                  {                       Opening Brace
     CC                  [hook]                  Hook
     CE                  [fork]                  Fork
 *   D0                  }                       Closing Brace
 *   E0                  /                       Reverse Slant
     EC                  [chair]                 Chair
     FA                  |                       Long Vertical Line
     FF                  EO                      Eight Ones
                   Figure 5: Special EBCDIC Graphics
  • ASCII Graphic

Winett [Page 9] RFC 183 EBCDIC Codes and Their Mapping to ASCII July 21, 1971

      Hex Code   Graphic                 Name
 **      A0      -                       Superscript Minus
 *       A1      [degree]                Degree
 *       B0      [superscript 0]         Superscript Zero
 *       B1      [superscript 1]         Superscript One
 *       B2      [superscript 2]         Superscript Two
 *       B3      [superscript 3]         Superscript Three
         B4      [superscript 4]         Superscript Four
         B5      [superscript 5]         Superscript Five
         B6      [superscript 6]         Superscript Six
         B7      [superscript 7]         Superscript Seven
         B8      [superscript 8]         Superscript Eight
         B9      [superscript 9]         Superscript Nine
         SB      {                       Left Brace
         SC      [equal or less than]    Equal or Less Than
         SD      [superscript (]         Superscript Left Parenthesis
         SE      [superscript +]         Superscript Plus Sign
         SF      +                       Plotting Cross
         9B      }                       Right Brace
         9C      [lozenge]               Lozenge
         9D      [superscript )]         Superscript Right Parenthesis
         9E      [plus or minus]         Plus or Minus
         9F      [histogram]             Histogram
         AB      [lower left corner]     Lower Left Corner
         AC      [upper left corner]     Upper Left Corner
         AD      [                       Open Square Bracket
         AE      [= or >]                Equal or Greater Than
         AF      [bullet]                Bullet (Plotting Circle)
         EB      [lower right corner]    Lower Right Corner
         EC      [upper right corner]    Upper Right Corner
         ED      ]                       Close Square Bracket
         EE      [not equal]             Not equal
         EF      ---                     Entended Dash
              Figure 6: Publishing and Printing Graphics
                        Also on the TN Print Chain
  • * Dual with the special EBCDIC graph c tilde
  • Dual with another graphic which is not on the TN print chain

Winett [Page 10] RFC 183 EBCDIC Codes and Their Mapping to ASCII July 21, 1971

     Hex Code    Graphic                 Name
         70      [Scandinavian accent]   Scandinavian Accent
         71      [carrot]                Circumflex
         72      [diaeresis]             Diaeresis
         73      /                       Diacritical Virgule
         74      '                       Acute Accent
         75      [superior .]            Superior Dot
         76      ,                       Cedilla
         77      [breve]                 Breve
         78      [caron]                 Caron
         8A      [up arrow]              Up Arrow
         9A      [dagger]                Dagger
  • B0 " Double Acute
  • B1 ' Inferior Hook
  • B2 - Macron
  • B3 , Inferior Comma
         CD      '                       Open Quote
         DB      [pound sign]            Pound Sign
         DC      [section sign]          Section Sign
         DD      [paragraph sign]        Paragraph Sign
         ED      '                       Close Quote
           Figure 7: Publishing and Printing Graphics
                     not on the TN Print Chain
  • Dual with another graphic which is on the TN print chain

Winett [Page 11] RFC 183 EBCDIC Codes and Their Mapping to ASCII July 21, 1971

 Name        Graphic    Hex Code     Graphic       Name
 Tilde           ~       A1         [degree]       Degree
 Double Acute    "       B0        [superscript 0] Superscript Zero
 Inferior Hook   '       B1        [superscript 1] Superscript One
 Macron  -               B2        [superscript 2] Superscript Two
 Inferior Comma ,        B3        [superscript 3] Superscript Three
                    Figure 8: Graphic Duals
 __________________________________________________________________
 Codes           Graphics               Name
 AF--75             .                   Bullet--Superior Dot
 8B--C0             {                   Left Brace--Opening Brace
 9B--D0             }                   Right Brace--Closing Brace
 61--73             /                   Slash--Diacritical Virgule
 A1--7.0         [degree]               Degree--Scandinavian Accent
 4F--FA             |                   Logical Or--Long Vertical Mark
 6B--76--B3         ,                   Comma--Cedilla-Inferior Comma
 60--B2             -                   Dash--Macron
                     Figure 9: Similar Graphics
 ____________________________________________________________________
 Name            Control  Hex Code  Graphic      Name
 Group Mark        GM      4F          |         Logical or
 Mode Change       MC      5F      [upper right corner] Logical Not
 Plus Zero         PZ      C0          {         Opening Brace
 Minus Zero        MZ      D0          }         Closing Brace
 Record Mark       RM      E0          \        Reverse Slant
 Word Separator    WS      6D          __        Underscore
 Segment Mark      SM      6F           ?        Question Mark
 Substitute Blank  SB      7A           :        Colon
 Tape Mark         TM      7F           "        Quotation Marks
                   Figure 10: Graphic Control Duals
 ____________________________________________________________________
 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.

Winett [Page 12]

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