BCD (6-bit) - AbsoluteAstronomy.com

Six-bit BCD code alphanumeric BCD, or alphameric BCD is a six-bit character code used by mainframe

Mainframe computer

Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

computers to represent the numerals, the Latin letters, and some additional characters. It represents the numerals as binary coded decimal preceded by two zero bits.

Among the vendors using six-bit BCD were: Burroughs, Bull

Bull

Bull usually refers to an uncastrated adult male bovine.Bull may also refer to:-Entertainment:* Bull , an original show on the TNT Network* "Bull" , an episode of television series CSI: Crime Scene Investigation...

, CDC

Control Data Corporation

Control Data Corporation was a supercomputer firm. For most of the 1960s, it built the fastest computers in the world by far, only losing that crown in the 1970s after Seymour Cray left the company to found Cray Research, Inc....

, IBM

IBM

International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

, General Electric

General Electric

General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

, GECn, NCR

NCR Corporation

NCR Corporation is an American technology company specializing in kiosk products for the retail, financial, travel, healthcare, food service, entertainment, gaming and public sector industries. Its main products are self-service kiosks, point-of-sale terminals, automated teller machines, check...

, Siemens

Siemens

Siemens may refer toSiemens, a German family name carried by generations of telecommunications industrialists, including:* Werner von Siemens , inventor, founder of Siemens AG...

, Sperry

Sperry Corporation

Sperry Corporation was a major American equipment and electronics company whose existence spanned more than seven decades of the twentieth century...

- Univac

UNIVAC

UNIVAC is the name of a business unit and division of the Remington Rand company formed by the 1950 purchase of the Eckert-Mauchly Computer Corporation, founded four years earlier by ENIAC inventors J. Presper Eckert and John Mauchly, and the associated line of computers which continues to this day...

, etc.

IBM created a code for the punch cards in the 1960s that expanded to other manufacturers.

The BCD (6-bit) code was the adaptation of the punched card code to binary code

Binary code

A binary code is a way of representing text or computer processor instructions by the use of the binary number system's two-binary digits 0 and 1. This is accomplished by assigning a bit string to each particular symbol or instruction...

BCD code variations

There are different versions of the BCD (6-bit) code. There are at least 4 versions with some different characters, and others with a completely different mapping such as BCD code "FIELDATA".

It has no control character

Control character

In computing and telecommunication, a control character or non-printing character is a code point in a character set, that does not in itself represent a written symbol.It is in-band signaling in the context of character encoding....

s, 0x20 is the space character, the character Ñ was @ for most manufacturers (Bull, NCR, and Control Data), but there was an inconsistency in converting to 7-bit ASCII code for / character was chosen.

GBCD code

Below is the table of GBCD code, a variant of BCD code.

Numbers, capital letters A through Z, a minimum of symbols and no control character

Control character

.

To emulate control character some symblos got special meaning like #,?,! when followed by e.g. a number. CR/LF is '!1', FF='! ' etc.

\|000	001	002	003	004	005	006	007
000	0	1	2	3	4	5	6	7
001	8	9	[	#	@	:	>	?
002		A	B	C	D	E	F	G
003	H	I	&	.	]	(	<	\
004	^	J	K	L	M	N	O	P
005	Q	R
$	*	)	;	'
006	`	/	S	T	U	V	W	X
007	Y	Z	<	,	%	=	"	!
\|000	001	002	003	004	005	006	007

Binary map of GBCD code

Numbers, capital letters A through Z, a minimum of symbols and no control character

Control character




0 - 00- 0 0 0  0 0 0


1 - 01- 0 0 0  0 0 1


2 - 02- 0 0 0  0 1 0


3 - 03- 0 0 0  0 1 1


4 - 04- 0 0 0  1 0 0


5 - 05- 0 0 0  1 0 1


6 - 06- 0 0 0  1 1 0


7 - 07- 0 0 0  1 1 1


8 - 10- 0 0 1  0 0 0


9 - 11- 0 0 1  0 0 1


[ - 12- 0 0 1  0 1 0


# - 13- 0 0 1  0 1 1


@ - 14- 0 0 1  1 0 0


: - 15- 0 0 1  1 0 1


> - 16- 0 0 1  1 1 0 (= >)


? - 17- 0 0 1  1 1 1


_ - 20- 0 1 0  0 0 0 (space)


A - 21- 0 1 0  0 0 1


B - 22- 0 1 0  0 1 0


C - 23- 0 1 0  0 1 1


D - 24- 0 1 0  1 0 0


E - 25- 0 1 0  1 0 1


F - 26- 0 1 0  1 1 0


G - 27- 0 1 0  1 1 1


H - 30- 0 1 1  0 0 0


I - 31- 0 1 1  0 0 1


& - 32- 0 1 1  0 1 0


. - 33- 0 1 1  0 1 1


] - 34- 0 1 1  1 0 0


( - 35- 0 1 1  1 0 1


< - 36- 0 1 1  1 1 0 (= <)


\ - 37- 0 1 1  1 1 1


^ - 40- 1 0 0  0 0 0 (arrow ^)


J - 41- 1 0 0  0 0 1


K - 42- 1 0 0  0 1 0


L - 43- 1 0 0  0 1 1


M - 44- 1 0 0  1 0 0


N - 45- 1 0 0  1 0 1


O - 46- 1 0 0  1 1 0


P - 47- 1 0 0  1 1 1


Q - 50- 1 0 1  0 0 0


R - 51- 1 0 1  0 0 1


- - 52- 1 0 1  0 1 0


$ - 53- 1 0 1  0 1 1


* - 54- 1 0 1  1 0 0


) - 55- 1 0 1  1 0 1


; - 56- 1 0 1  1 1 0


' - 57- 1 0 1  1 1 1


` - 60- 1 1 0  0 0 0


/ - 61- 1 1 0  0 0 1


S - 62- 1 1 0  0 1 0


T - 63- 1 1 0  0 1 1


U - 64- 1 1 0  1 0 0


V - 65- 1 1 0  1 0 1


W - 66- 1 1 0  1 1 0


X - 67- 1 1 0  1 1 1


Y - 70- 1 1 1  0 0 0


Z - 71- 1 1 1  0 0 1


< - 72- 1 1 1  0 1 0 (arrow <)


, - 73- 1 1 1  0 1 1


% - 74- 1 1 1  1 0 0


= - 75- 1 1 1  1 0 1


" - 76- 1 1 1  1 1 0


! - 77- 1 1 1  1 1 1

BCD code variations

GBCD code

Binary map of GBCD code

See also

Further Reading