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.
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?
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
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.
