Barcode 128

Code 128 is a type of barcode that encodes alphanumeric data as black bars and white spaces of varying widths.

It is widely used in logistics, transportation, and inventory management due to its compact size and robustness.

A widespread industrial application is the GS1-128 standard (formerly EAN-128), which uses Code 128 symbology to structure standardized logistics data (product identifiers, batch numbers, etc.).

A 128 barcode consists of a series of alternating groups of three black bars and three white spaces of varying widths (between 1 and 4 units wide).

The standard describes three encoding tables: Code 128A, Code 128B, and Code 128C. These three sets of codes allow for the representation of all ASCII characters from 0 to 127, as well as special functions (FNC1 to FNC4).

The 128 barcode begins with a series of dashes indicating Start and ends with End. Between these dashes are the characters of the message to be encrypted, each represented by six bars (three black and three white) of length 11 units.

To encode a string of characters:

1 - Start with the Start symbol corresponding to the encoding table being used.

2 - Convert each character according to the lookup table and insert the corresponding strokes

3 - Calculate the check digit (see below) and insert it afterward

4 - End with the Stop symbol

Decoding involves reading the widths of the bars and spaces. This process is broken down into several steps.

1 - Identify the starting symbol (Start A, B, or C)

2 - Divide the sequence into blocks of 6 bars (11 units wide)

3 - Convert each pattern into a numerical value (0 to 106)

4 - Verify the check digit.

5 - Translate the values according to the active code set.

The check digit is calculated by summing the value of the starting symbol with each value encoded in the barcode, multiplied by its position, all modulo 103.

The barcode may have a conventional graphical form (black and white lines similar to zebra's stripes) or a binary equivalent (of 0 to vacuum and 1 white bars) or a base 4 code (1,2,3 and 4 for the size of the bar, alternating black and white).

The bar code may have a variable length. It begins (usually) by Start and ends with the character End or Stop (see table).

To encode a message of N characters, the number of units needed (between the first and last black bar) is 11 × (N + 2) + 13 units

The concepts of optical readers (laser), scanners, or barcode software/mobile applications are clues.

Coding table 128A has ASCII characters from 00 to 95.

Coding table 128B has ASCII characters from 32 to 127.

Coding table 128C has all numeric values from 00 to 99.

id	bands	binary	128A	128B	128C
0	212222	11011001100	Space	Space	00
1	222122	11001101100	!	!	01
2	222221	11001100110	"	"	02
3	121223	10010011000	#	#	03
4	121322	10010001100	$	$	04
5	131222	10001001100	%	%	05
6	122213	10011001000	&	&	06
7	122312	10011000100			07
8	132212	10001100100	(	(	08
9	221213	11001001000	)	)	09
10	221312	11001000100	*	*	10
11	231212	11000100100	+	+	11
12	112232	10110011100	,	,	12
13	122132	10011011100	-	-	13
14	122231	10011001110	.	.	14
15	113222	10111001100	/	/	15
16	123122	10011101100	0	0	16
17	123221	10011100110	1	1	17
18	223211	11001110010	2	2	18
19	221132	11001011100	3	3	19
20	221231	11001001110	4	4	20
21	213212	11011100100	5	5	21
22	223112	11001110100	6	6	22
23	312131	11101101110	7	7	23
24	311222	11101001100	8	8	24
25	321122	11100101100	9	9	25
26	321221	11100100110	:	:	26
27	312212	11101100100	;	;	27
28	322112	11100110100	<	<	28
29	322211	11100110010	=	=	29
30	212123	11011011000	>	>	30
31	212321	11011000110	?	?	31
32	232121	11000110110	@	@	32
33	111323	10100011000	A	A	33
34	131123	10001011000	B	B	34
35	131321	10001000110	C	C	35
36	112313	10110001000	D	D	36
37	132113	10001101000	E	E	37
38	132311	10001100010	F	F	38
39	211313	11010001000	G	G	39
40	231113	11000101000	H	H	40
41	231311	11000100010	I	I	41
42	112133	10110111000	J	J	42
43	112331	10110001110	K	K	43
44	132131	10001101110	L	L	44
45	113123	10111011000	M	M	45
46	113321	10111000110	N	N	46
47	133121	10001110110	O	O	47
48	313121	11101110110	P	P	48
49	211331	11010001110	Q	Q	49
50	231131	11000101110	R	R	50
51	213113	11011101000	S	S	51
52	213311	11011100010	T	T	52
53	213131	11011101110	U	U	53
54	311123	11101011000	V	V	54
55	311321	11101000110	W	W	55
56	331121	11100010110	X	X	56
57	312113	11101101000	Y	Y	57
58	312311	11101100010	Z	Z	58
59	332111	11100011010	[	[	59
60	314111	11101111010	\	\	60
61	221411	11001000010	]	]	61
62	431111	11110001010	^	^	62
63	111224	10100110000	_	_	63
64	111422	10100001100	NUL	`	64
65	121124	10010110000	SOH	a	65
66	121421	10010000110	STX	b	66
67	141122	10000101100	ETX	c	67
68	141221	10000100110	EOT	d	68
69	112214	10110010000	ENQ	e	69
70	112412	10110000100	ACK	f	70
71	122114	10011010000	BEL	g	71
72	122411	10011000010	BS	h	72
73	142112	10000110100	HT	i	73
74	142211	10000110010	LF	j	74
75	241211	11000010010	VT	k	75
76	221114	11001010000	FF	l	76
77	413111	11110111010	CR	m	77
78	241112	11000010100	SO	n	78
79	134111	10001111010	SI	o	79
80	111242	10100111100	DLE	p	80
81	121142	10010111100	DC1	q	81
82	121241	10010011110	DC2	r	82
83	114212	10111100100	DC3	s	83
84	124112	10011110100	DC4	t	84
85	124211	10011110010	NAK	u	85
86	411212	11110100100	SYN	v	86
87	421112	11110010100	ETB	w	87
88	421211	11110010010	CAN	x	88
89	212141	11011011110	EM	y	89
90	214121	11011110110	SUB	z	90
91	412121	11110110110	ESC	{	91
92	111143	10101111000	FS	|	92
93	111341	10100011110	GS	}	93
94	131141	10001011110	RS	~	94
95	114113	10111101000	US	DEL	95
96	114311	10111100010	FNC3	FNC3	96
97	411113	11110101000	FNC2	FNC2	97
98	411311	11110100010	ShiftB	ShiftA	98
99	113141	10111011110	Code C	Code C	99
100	114131	10111101110	Code B	FNC4	Code B
101	311141	11101011110	FNC4	Code A	Code A
102	411131	11110101110	FNC1	FNC1	FNC1
103	211412	11010000100	Start A	Start A	Start A
104	211214	11010010000	Start B	Start B	Start B
105	211232	11010011100	Start C	Start C	Start C
106	2331112	1100011101011	Stop	Stop	Stop

Code 128 structurally has three variants: 128A, 128B, and 128C, which are internal coding sets.

Code 128 serves as a standard for GS1-128 codes (formerly EAN-128) for logistics or HIBC for the medical sector.

Other barcode standards exist: EAN-13, EAN-8, Code 39, and Code 93, each with its own structure.

Code 128 encodes a sequence of characters or a number without imposing any intrinsic meaning. Its meaning depends entirely on the system interpreting it; it can mean anything: the decoded number or text could be a product identifier, a tracking number, an internal reference, etc. Without access to the corresponding database, it remains a simple sequence of characters/numbers.

The standard does not set a strict length limit. However, the practical limit depends on the print resolution and the minimum read width, which is determined by the optical reader's capacity. A barcode printed or displayed too small or too large will be unusable by most scanners.

dCode shares a character font file (ttf font) here (unknown source, unknown licence)