RFC 183
EBCDIC Codes and Their Mapping to ASCII
RFC 183: The EBCDIC Codes and Their Mapping to ASCII 💖
okay bestie, this one is from July 21, 1971 🎀 It was written by J.M. Winett at Lincoln Laboratory, and it sits in the Network Working Group with NIC number 7127. The categories are D.2 and D.3, and it's related to RFCs 109, 110, 105, and 158 ✨ The title block doesn't list any RFCs it obsoletes or updates.
Abstract 🦋
okay so the big goal is making ASCII codes map to EBCDIC codes in one consistent way across the whole ARPA Network 🌐 This RFC defines the IBM Standard Extended BCD Interchanged Code to do exactly that. ✨
Introduction 🌸
the IBM Corporate Systems Standard, Extended BCD Interchanged Code (EBCDIC), defines 8-bit graphic and control codes (see Figure 1) 🧚 The basic EBCDIC set has 54 controls (space included) and 88 graphics. It gets extended with 10 special graphics and 1 special control (EO). Those special graphics come from the 7-bit hollerith code and include 6 ASCII graphics 💜 It's extended even more with the publishing and printing graphics option, which specifies 52 graphics. Of those, 32 show up on the IBM TN print chain. Four of them are duals with graphics that aren't on the TN print chain, and one graphic (degree) is dual with a graphic in the basic code's special graphics set (tilde) 🫶
It's really desirable to map ASCII codes to their EBCDIC counterparts in a consistent way across the ARPA network, no cap 💅
Here's the lay of the land: each of the 34 ASCII controls (space and delete included) has a matching BDCDIC control, like ASCII control DC3 going to EBCDIC X'13' 🍓 For 85 of the 94 ASCII graphics there's a matching graphic in the basic EBCDIC set. The other 9 ASCII graphics can be mapped in three different ways, which is where the fun (and the decisions) start 😭
I. IBM Correspondence 👑
a) okay so IBM recommends these 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'ngl, the EBCDIC graphic for exclamation point (!) is not the one picked to match ASCII exclamation point (!). That would've been the sensible choice, but it means another code has to be used to represent this graphic 🙈
b) for the other ASCII graphics, special EBCDIC graphics would be used instead 🎀
Graphic Code
l X'6A'
l X'79'
[diagonal slash] X'A1'
~ X'E0'
[diagonal slash] XC0'
{ XD0'
}II. Publishing Correspondence 🌈
a) these special EBCDIC graphics get paired with their matching ASCII graphics 🧚
Graphic Code
[carrot] X'71'
[ X'AD'
] X'BD'
{ X'8B'
} X'9B'the codes for open bracket and close bracket were chosen because these graphics show up on the TN print chain 🦋 The codes for left brace and right brace were chosen over the special graphics set codes for opening and closing brace, respectively, because those graphics look similar and also appear on the TN print chain. main character energy for the TN print chain, honestly 💅
III. Graphical Correspondence ✨
a) these basic EBCDIC graphics get matched with the ASCII graphics that look most like them 👀
| X'4F' with |
|
[upper right corner] X'5F' with ~b) the basic EBCDIC graphic for cent gets matched with the ASCII graphic for reverse slash 🔥
[cent] X'4A' with [diagonal slash]this one's giving logic: the cent graphic isn't an ASCII graphic, and it's the only graphic in the basic EBCDIC set that wouldn't otherwise be linked to any ASCII graphic 🫶
c) the special EBCDIC grave accent graphic gets associated with its matching ASCII graphic 🌸
` X'79'd) these publishing EBCDIC graphics get matched with their corresponding ASCII graphics 🎀
[carrot] X'71'
[ X'AD'
] X'BD'
{ X'8B'
} X'9B'same tea as before: the open and close bracket codes were picked since these graphics appear on the TN print chain, and the left and right brace codes were picked over the special graphics set codes for opening and closing brace because they look similar and also show up on the TN print chain 💖
Standards: 💜
okay so, for the ASCII-to-EBCDIC and EBCDIC-to-ASCII mapping to become a real standard, I'd love comments on all of this from every site whose operating system uses EBCDIC as its internal code 🙏
Telnet Codes: 🧚
for sites that want to offer TELNET services communicating with an EBCDIC code, a standard code has to be specified 🫶 The codes in Figure 1 can form the basis for that standard. The TELNET control codes need specific codes too, and these are the ones I suggest 💅
Hex Code
sync 38
break 39
NOP 3A
Return to ASCII FF
No echo 14
Echo 23
Hide input 24and now for the tea 🍵 To stop one code from being used for two graphics, I propose that the TN graphics get linked to their corresponding codes. The graphic tilde (~) could go to code X'E1' instead of staying paired with degree. This wouldn't change anything if the Graphical Correspondence is used for the EBCDIC-to-ASCII mapping with code X'5F' for logical not linked to tilde. The other publishing and printing graphics (Double Acute, Inferior Hook, Macron, and Inferior Comma) aren't on the TN print chain, but they share codes with TN print chain graphics, so they wouldn't count as part of the standard EBCDIC code 😭
🎀 that's part 1 of 2! part 2 has the EBCDIC questionnaire, the figures, and the full control code table, so stay tuned, bestie 🦋✨
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 FunctionsOkay so here's the vibe for the control character categories, bestie 💅 Each one gets its own little job description, and I'm obsessed with how organized it is ✨
CC ([illegible] Control) is a functional character [illegible] to control or facilitate transmission of introducing [illegible] communication networks. 📡
FB (Format Bisector) is a functional character that controls the layout of positioning or information in printing or display devices. 🎀
IS (Information Separator) is a character used to separate and qualify information in a logical sense. There's a group of four of these, and they're meant to be used in a hierarchical order. 🌸
DC (Device Control) is a functional character used for controlling ancillary devices associated with data processing or telecommunication systems, more especially switching devices "on" and "off". 🔌
ED (Edit and Mark) is a control character used by the System/[illegible]...and Mark ([illegible]) instruction for formatting alphanumeric fields. 💖
GH (Graphic Control) is a control character indicating that the core combinations which follow are to be [illegible] in a particular code table, depending on the particular control character. 🦋
CU (Customer Use) is a character excluded from future assignment by IBM. These "protected" codes are meant for customer systems, so their use won't clash 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. 🫶
📦 where this page comes from
- ietf: rfc183 1971-07
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms