Lotus Multi-Byte Character Set

The Lotus Multi-Byte Character Set (LMBCS) is a proprietary multi-byte character encoding originally conceived in 1988 at Lotus Development Corporation with input from Bob Balaban and others.^[1] Created around the same time and addressing some of the same problems, LMBCS could be viewed as parallel development and possible alternative to Unicode.^[1] For maximum compatibility, later issues of LMBCS incorporate UTF-16 as a subset.^[2][3]

Commercially, LMBCS was first introduced as the default character set of Lotus 1-2-3 Release 3 for DOS in March 1989^[1][4] and Lotus 1-2-3/G Release 1 for OS/2^[1] in 1990 replacing the 8-bit Lotus International Character Set (LICS) and ASCII used in earlier DOS-only versions of Lotus 1-2-3 and Symphony.^[5] LMBCS is also used in IBM/Lotus SmartSuite, Notes and Domino,^[1] as well as in a number of third-party products.

LMBCS encodes the characters required for languages using the Latin,^[6] Arabic, Hebrew, Greek and Cyrillic^[6] scripts, the Thai, Chinese, Japanese^[6] and Korean writing systems, and technical symbols.

Technically, LMBCS is a lead-byte encoding where code point 00_hex as well as code points 20_hex (32) to 7F_hex (127) are identical to ASCII^[1] (as well as to LICS).^[5]

Code point 00_hex is always treated as NUL character to ensure maximum code compatibility with existing software libraries dealing with null-terminated strings^[1] in many programming languages such as C.^[a] This applies even to the UTF-16be codes, where code words with the form xx00_hex are mapped to private-use codes with the form F6xx_hex during encoding in order to avoid the use of NUL bytes,^[7] and to escaped control characters, where 20_hex is added to the C0 (but not C1) control characters following the 0F_hex lead byte.^[7]

Code points 01_hex to 1F_hex, which serve as control codes in ASCII, are used as lead bytes to switch the definition of code points above 7F_hex between several code groups (similar to code pages) and at the same time determine either a single- or multi-byte nature for the corresponding code group.^[1]

For example, code group 1 (with group byte 01_hex)^[1] is almost identical to the SBCS code page 850, whereas code group 16 (with group byte 10_hex)^[1] is similar to the Japanese MBCS code page 932. Multi-byte characters can thus occupy two or three bytes.^[7][6]

In canonical LMBCS, each character starts with its group byte.^[1] To reduce the length, in optimized or compressed LMBCS a default code group or optimization group code can be defined on a per application or process basis (ideally chosen according to the highest likelihood of occurrence)^[1] and must be communicated to the interpreting code in some way (f.e. by specifying the corresponding "LMBCS-n" name).^[8] Thereby, the group byte can be omitted for these characters.^[1] Lotus 1-2-3 retrieves the optimization group code from the file header of the corresponding source file,^[7] whereas for Lotus Notes the optimization group code is fixed to be always 01_hex.^[2][7]

Default	Group	Bytes	Description
N/A	00hex	1[7]	NUL
LMBCS-1	01hex	2[7]	Code page 850 (DOS Latin-1)[2][7]
LMBCS-2	02hex	2[7]	Code page 851 (DOS Greek)[2][7]
LMBCS-3	03hex	2[7]	Code page 1255 (Windows Hebrew)[2][7]
LMBCS-4	04hex	2[7]	Code page 1256 (Windows Arabic)[2][7]
LMBCS-5	05hex	2[7]	Code page 1251 (Windows Cyrillic)[2][7]
LMBCS-6	06hex	2[7]	Code page 852 (DOS Latin-2)[2][7]
N/A	07hex	1[7]	BEL[2]
LMBCS-8	08hex	2[7]	Code page 1254 (Windows Turkish)[2][9][7]
N/A	09hex	1[7]	TAB[2][9][7]
N/A	0Ahex	1[7]	LF[2][9][7]
LMBCS-11	0Bhex	2[7]	Code page 874 (Thai)[9][7]
(LMBCS-12)	0Chex	2[7]	Reserved[2]
N/A	0Dhex	1[7]	CR[2][9][7]
(LMBCS-14)	0Ehex	2[7]	Reserved[2]
(LMBCS-15)	0Fhex	2[7]	Remapped C0/C1 control codes[7]
LMBCS-16	10hex	3[7]	Code page 932/[2]943[7] (Japanese / Shift-JIS)[2][9]
LMBCS-17	11hex	3[7]	Code page 949/[2]1261[7] (Korean)[2][9]
LMBCS-18	12hex	3[7]	Code page 950[2][7] (Traditional Chinese / Taiwan / Big5)[2][9]
LMBCS-19	13hex	3[7]	Code page 936/[2]1386[7] (Simplified Chinese)[2][9]
(LMBCS-20)	14hex	3[7]	UTF-16 (Unicode)[2][3][7]
N/A	15hex	3	Reserved[2]
N/A	16hex	3	Reserved[2]
N/A	17hex	3	Reserved[2]
N/A	18hex	3	Reserved[2]
N/A	19hex	1[7]	Lotus 1-2-3 system range[9][7]
N/A	1Ahex	3	Reserved[2]
N/A	1Bhex	3	Reserved[2]
N/A	1Chex	3	Reserved[2]
N/A	1Dhex	3	Reserved[2]
N/A	1Ehex	3	Reserved[2]
N/A	1Fhex	3	Reserved[2]

Without prefix byte the code points 32 (20_hex) to 127 (7F_hex) are interpreted as follows (corresponding to LMBCS codes 32 to 127):

Single byte codes (ASCII/ISO-646-US^[10])

	0	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
2x	SP	!	"	#	$	%	&	'	(	)	*	+	,	-	.	/
3x	0	1	2	3	4	5	6	7	8	9	:	;	<	=	>	?
4x	@	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O
5x	P	Q	R	S	T	U	V	W	X	Y	Z	[	\	]	^	_
6x	`	a	b	c	d	e	f	g	h	i	j	k	l	m	n	o
7x	p	q	r	s	t	u	v	w	x	y	z	{	|	}	~	DEL/⌂

LMBCS group 1 code points 128 (80_hex) to 255 (FF_hex) are identical to the corresponding code points in code page 850 (DOS Latin-1), whereas code points 1 (01_hex) to 127 (7F_hex) are defined according to the following exception list (corresponding to LMBCS codes 256 to 383):

LMBCS Group 1, lower half^[11][10]

	0	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
0x	NUL	☺	☻	♥	♦	♣	♠	•	◘	○	◙	♂	♀	♪	♫	☼
1x	►	◄	↕	‼	¶	§	▬	↨	↑	↓	→	←	∟	↔	▲	▼
2x	¨	~	˚	^	`	´	“	'	…	-[b]	—	‘[c]	’[c]		‹	›
3x	¨[d]	~[d]	˚[d]	^[d]	`[d]	´[d]	„	‚	”	‗		NBSP[c]		�[c]
4x	Œ	œ	Ÿ	˙[c]	˚[c][d]		╞	╟	▌	▐	◊[c]	⌘[c]	[c]	[c]	Ω[c]
5x	╨	╤	╥	╙	╘	╒	╓	╫	╪	╡	╢	╖	╕	╜	╛	╧
6x	ij	IJ	fi	fl	ʼn	ŀ	Ŀ	¯[c]	˘[c]	˝[c]	˛[c]	ˇ[c]	~[c][d]	^[c][d]
7x	†	‡	Ħ[c]	ħ[c]	Ŧ[c]	ŧ[c]	™	ℓ	Ŋ[c]	ŋ[c]	ĸ[c]		Kr[e]	⌐	₤	₧

LMBCS group 2 code points 128 (80_hex) to 255 (FF_hex) are identical to the corresponding code points in code page 851 (DOS Greek), whereas code points 1 (01_hex) to 127 (7F_hex) are defined according to the following exception list:^[f]

LMBCS Group 2, lower half^[11]

	0	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
0x	NUL	ͺ	΅	Ϊ	Ϋ	―	΄	ʼ	ʽ	‾						
1x			⇕	⅞	⅝	⅜	⅛		⇑	⇓	⇒	⇐		⇔		
2x																
3x																
4x	∠	∇														
5x	∂	ℵ	ℑ	ℜ								∋	∈	∉	⊆	⊇
6x	⊗	⊕	✓	⋀	∁	∫	∀	∃		′	″	∞	∝	φ	∪	∩
7x	≡	≅	≥	≤	⌠	⌡	≠	≈	⁄	∙	‰	√	ⁿ	∅	⊂	⊃

LMBCS group 6 code points 128 (80_hex) to 255 (FF_hex) are identical to the corresponding code points in code page 852 (DOS Latin-2), whereas code points 1 (01_hex) to 127 (7F_hex) are defined according to the following exception list:^[f]

LMBCS Group 6, lower half^[11]

	0	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
0x	NUL	ā	Ĉ	ĉ	Ċ	ċ	Ē	ē	Ė	ė	Ĝ	ĝ	Ġ	ġ	Ģ	ģ
1x	Ĥ	ĥ	Ĩ	ĩ	Ī	ī	Į	į	Ĵ	ĵ	Ķ	ķ	Ļ	ļ	Ņ	ņ
2x	Ō	ō	Ŗ	ŗ	Ŝ	ŝ	Ũ	ũ	Ū	ū	Ŭ	ŭ	Ų	ų	Ā
3x
4x
5x
6x
7x

• Compose key
• GB 18030
• Standard Compression Scheme for Unicode (SCSU)
• Symbol (typeface)
• Xerox Character Code Standard (XCCS)

• Born, Günter [in German] (December 2000) [1990]. "Kapitel 2. LOTUS 1-2-3-Format (WK3)" [Chapter 2. Lotus 1-2-3 WK3 format]. Dateiformate – Eine Referenz – Tabellenkalkulation, Text, Grafik, Multimedia, Sound und Internet [File formats – a reference – spreadsheets, text, graphics, multimedia, sound and internet] (PDF) (in German). Bonn, Germany: Galileo Computing. ISBN 3-934358-83-7. Archived (PDF) from the original on 2016-11-29. Retrieved 2016-11-28. (Includes some information about LMBCS and Lotus system ranges.)
• "LMBCS tables". User's Guide – 123 Release 4 for Windows (Fax). 1995 [1994-01-01]. CHAPTER: Appendix A Using the Lotus Multibyte Character Set. Fax 10955. Retrieved 2016-12-06.^{[dead ftp link]} (To view documents see Help:FTP)
• "Entering LMBCS characters". User's Guide – 123 Release 4 for Windows (Fax). 1995 [1994-01-01]. CHAPTER: Appendix A Using the Lotus Multibyte Character Set. Fax 10954. Retrieved 2016-12-06.^{[dead ftp link]} (To view documents see Help:FTP)
• Lotus Support. "Notes from Support: SMTP MTA International Character Sets". IBM developerWorks. IBM. Archived from the original on 2016-12-08. Retrieved 2016-12-08.
• Character Translation Files (.CTF) by Notes 2.x and Country Language Service (.CLS) files by Notes 3.0 and higher contain information about LMBCS translation into other codepages [2] [3]

• Berntrop-Bos, Lars (2014-07-10). "Blast from the past: LMBCS tables for Windows, OS/2, Unix and Macintosh". Archived from the original on 2016-11-26. Retrieved 2016-11-26.