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This is a modified version of the Internet RFC suitable for machine-translating. Original version is available here: 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. Telnet Codes:

Winett [Page 3]


RFC 183         EBCDIC Codes and Their Mapping to ASCII    July 21, 1971

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 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

Winett [Page 11]


RFC 183         EBCDIC Codes and Their Mapping to ASCII    July 21, 1971

                      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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