FOCAL character set

In computing FOCAL character set refers to a group of 8-bit single byte character sets introduced by Hewlett-Packard since 1979. It was used in several RPN calculators supporting the FOCAL programming language, like the HP-41C/CV/CX as well as the later HP-42S,[1][2] which was introduced in 1988[1][2] and produced up to 1995. As such, it is also used by SwissMicros' DM41/L, both introduced in 2015, and is implicitly supported by the DM42, introduced in 2017 (although the later calculator utilizes Free42, which is based on Unicode internally).

Character set

The character set is derived from ASCII, but with the control code range and some high bit characters replaced by various special characters.

FOCAL character set (HP-41C/CV/CX / HP 82143A)[3][4]

	_0	_1	_2	_3	_4	_5	_6	_7	_8	_9	_A	_B	_C	_D	_E	_F
0_ 0	‾/♦ 203E/2666	∝? 221D?	x̅/ā 0078 0305/0101	← 2190	α 03B1	β 03B2	Γ 0393	↓ 2193	Δ 0394	σ 03C3	♦ 2666	λ 03BB	µ/μ 00B5/03BC	∡/∠ 2221/2220	τ 03C4	Φ 03A6
1_ 16	θ 03B8	Ω 03A9	&? 0026?	Å 00C5	å 00E5	Ä 00C4	ä 00E4	Ö 00D6	ö 00F6	Ü 00DC	ü 00FC	Æ 00C6	æ 00E6	≠ 2260	£/₤ 00A3/20A4	▒ 2592
2_ 32	SP 0020	! 0021	" 0022	# 0023	$ 0024	% 0025	& 0026	' 0027	( 0028	) 0029	* 002A	+ 002B	, 002C	- 002D	. 002E	/ 002F
3_ 48	0 0030	1 0031	2 0032	3 0033	4 0034	5 0035	6 0036	7 0037	8 0038	9 0039	: 003A	; 003B	< 003C	= 003D	> 003E	? 003F
4_ 64	@ 0040	A 0041	B 0042	C 0043	D 0044	E 0045	F 0046	G 0047	H 0048	I 0049	J 004A	K 004B	L 004C	M 004D	N 004E	O 004F
5_ 80	P 0050	Q 0051	R 0052	S 0053	T 0054	U 0055	V 0056	W 0057	X 0058	Y 0059	Z 005A	[ 005B	\ 005C	] 005D	↑/^ 2191/005E	_ 005F
6_ 96	`/⊤ 0060/22A4	a 0061	b 0062	c 0063	d 0064	e 0065	f 0066	g 0067	h 0068	i 0069	j 006A	k 006B	l 006C	m 006D	n 006E	o 006F
7_ 112	p 0070	q 0071	r 0072	s 0073	t 0074	u 0075	v 0076	w 0077	x 0078	y 0079	z 007A	π 03C0	| 007C	→ 2192	Σ 03A3	⊦[nb 1] 22A6?
8–F_	...

  Letter   Number   Punctuation   Symbol   Other   Undefined   Characters not in all versions

When Hewlett-Packard introduced the HP-42S in 1988, the FOCAL character set was revised to include more characters, including a number of characters already provided by the HP 82240A infrared thermo printer, which had been introduced in 1986,[5] as part of its extended variant of the 1985 revision of the HP Roman-8 character set,[6][7] although at completely different code points.

There is no code point definition for the euro sign in this character set.

Revised FOCAL character set (HP-42S)[1]

	_0	_1	_2	_3	_4	_5	_6	_7	_8	_9	_A	_B	_C	_D	_E	_F
0_ 0	÷ 00F7	× 00D7	√ 221A	∫ 222B	░ 2591	Σ 03A3	▶[nb 2] 25B6	π 03C0	¿ 00BF	≤ 2264	LF/EOT 000A/0004	≥ 2265	≠ 2260	↵ 21B5	↓ 2193	→ 2192
1_ 16	← 2190	µ/μ 00B5/03BC	£/₤ 00A3/20A4	° 00B0	Å 00C5	Ñ 00D1	Ä 00C4	∡/∠ 2221/2220	ᴇ/⏨ 1D07/23E8	Æ 00C6	…/‥ 2026/2025	␛ 241B	Ö 00D6	Ü 00DC	▒ 2592	■/· 25A0/00B7
2_ 32	SP 0020	! 0021	" 0022	# 0023	$ 0024	% 0025	& 0026	' 0027	( 0028	) 0029	* 002A	+ 002B	, 002C	- 002D	. 002E	/ 002F
3_ 48	0 0030	1 0031	2 0032	3 0033	4 0034	5 0035	6 0036	7 0037	8 0038	9 0039	: 003A	; 003B	< 003C	= 003D	> 003E	? 003F
4_ 64	@ 0040	A 0041	B 0042	C 0043	D 0044	E 0045	F 0046	G 0047	H 0048	I 0049	J 004A	K 004B	L 004C	M 004D	N 004E	O 004F
5_ 80	P 0050	Q 0051	R 0052	S 0053	T 0054	U 0055	V 0056	W 0057	X 0058	Y 0059	Z 005A	[ 005B	\ 005C	] 005D	↑/^ 2191/005E	_ 005F
6_ 96	` 0060	a 0061	b 0062	c 0063	d 0064	e 0065	f 0066	g 0067	h 0068	i 0069	j 006A	k 006B	l 006C	m 006D	n 006E	o 006F
7_ 112	p 0070	q 0071	r 0072	s 0073	t 0074	u 0075	v 0076	w 0077	x 0078	y 0079	z 007A	{ 007B	| 007C	} 007D	~ 007E	⊦[nb 1] 22A6?
8_ 128	¦? 00A6?	¥? 00A5?	▓? 2593?								␊ 240A
9–F_	...

Translation from HP-42S character set to the modified HP Roman-8 (supported by HP 82240A etc.) character set:

HP translation vector

	_0	_1	_2	_3	_4	_5	_6	_7	_8	_9	_A	_B	_C	_D	_E	_F
0_	0x81	0x82	0x83	0x84	0x04	0x85	0x86	0x87	0x08	0x89	0x04	0x8A	0x8B	0x0D	0x0E	0x8D
1_	0x8E	0x8F	0xAF	0xB3	0xA2	0xB6	0xD8	0xA0	0x18	0xD3	0x9B	0x1B	0xDA	0xDB	0x7F	0xF2
2_	0x20	0x21	0x22	0x23	0x24	0x25	0x26	0x27	0x28	0x29	0x2A	0x2B	0x2C	0x2D	0x2E	0x2F
3-6_	...
7_	0x70	0x71	0x72	0x73	0x74	0x75	0x76	0x77	0x78	0x79	0x7A	0x7B	0x7C	0x7D	0x7E	0x94
8_	0x80	0x81	0x82	0x83	0x84	0x85	0x86	0x87	0x88	0x89	0x90	0x8B	0x8C	0x8D	0x8E	0x8F
9-F_	...

See also

• Hewlett-Packard calculator character sets

Notes

1. The glyph at code point 127 (⊦) is called APPEND character in Hewlett-Packard terminology. In the HP-41C/CV/CX and HP-42S series of calculators, it is used to indicate that the following characters will be appended to the alpha register rather than replacing the existing contents of the register.
2. The glyph at code point 6 is called GOOSE character in Hewlett-Packard terminology. While U+25B6 (▶) is the preferred Unicode character for maximum cross-compatibility with established RPL character set mappings, Free42 since release 2.0.1 (2017-04-23) maps to U+25B8 (▸) instead.

References

1. RPN Scientific Calculator - Owner's Manual - HP-42S (PDF) (1 ed.). Hewlett-Packard. June 1988. pp. 288–291. 00042-90001, 00042-90002. Archived (PDF) from the original on 2018-01-04. Retrieved 2018-01-04.
2. HP-42S RPN Scientific - Programming Examples and Techniques (PDF) (1 ed.). Corvallis, OR, USA: Hewlett-Packard Company, Corvallis Division. July 1988. 00042-90020, 00042-90019. Archived (PDF) from the original on 2018-01-04. Retrieved 2018-01-04.
3. Hicks, David G. (2017) [1998]. "HP-41C Synthetic Programming". The Museum of HP Calculators (MoHPC). Archived from the original on 2018-01-06. Retrieved 2018-01-06.
4. Hicks, David G. (1997). "Graphic byte code table". The Museum of HP Calculators (MoHPC). Archived from the original on 2018-01-06. Retrieved 2018-01-06.
5. Nelson, Richard J. (May 2010). "HP 82240B IR Printer" (PDF). HP Solve (18). Archived from the original (PDF) on 2016-09-21. Retrieved 2016-09-21.
6. HP 82240A Infrared Printer (PDF) (2 ed.). Corvallis, OR, USA: Hewlett Packard, Portable Computer Division. October 1986. HP reorder number 82240-90001 (82240-90008). Archived (PDF) from the original on 2016-08-06. Retrieved 2016-08-06.
7. HP 82240B Infrared Printer (1 ed.). Corvallis, OR, USA: Hewlett Packard. August 1989. pp. 17–18. HP reorder number 82240-90014. Archived from the original on 2016-08-14. Retrieved 2016-08-01.

Further reading

• HP-41C Operating Manual - A Guide for the Experienced User (PDF). Hewlett-Packard Company. June 1980. 00041-90259. Archived (PDF) from the original on 2018-01-04. Retrieved 2018-01-04.
• Oerttel, Burkhard; Hümpfner, Reinhold; Meier, Bernhard; Schilli, Michael; Weber, Andreas; Leissner, Frank; Kaiser, Axel; Strewinski, Reinhard; von Borries, Sebastian; Dalkowski, Heinz; Fegert, Stefan (2014) [1989]. Fegert, Stefan; Dalkowski, Heinz (eds.). Programmsammlung für den HP-41 (PDF) (in German). Berlin, Germany: Heldermann Verlag. ISBN 3-88538-809-X. Archived (PDF) from the original on 2018-01-04. Retrieved 2018-01-04.