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.
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.
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:
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.
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.]
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)
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
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
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
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
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
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.
