TRS-80 character set

The TRS-80 computer manufacturered by Tandy / Radio Shack contains an 8-bit character set.[1] It is partially derived from ASCII, and shares the code points from 32 - 95 on the standard model. Code points 96 - 127 are supported on models that have been fitted with a lower-case upgrade.[2]

The character set consists of letters, various numeric and special characters[1] as well as 64 semigraphics called squots (square dots) from a 2×3 matrix.[3] These were located at code points 128 to 191 with bits 5-0 following their binary representation,[3] similar to alpha-mosaic characters in World System Teletext.[4] These characters were used for graphics in games, such as Android Nim.[5]

Character set

The following table shows the TRS-80 model I character set. Each character is shown with a potential Unicode equivalent. Space and control characters are represented by the abbreviations for their names.

TRS-80 model I character set[6][3][7][8]

	_0	_1	_2	_3	_4	_5	_6	_7	_8	_9	_A	_B	_C	_D	_E	_F
0_ 0									BS[lower-alpha 1] 0008		LF 000A			CR 000D	con[lower-alpha 2]	coff[lower-alpha 3]
1_ 16							[lower-alpha 4]	32[lower-alpha 5]	←[lower-alpha 6]	→[lower-alpha 7]	↓[lower-alpha 8]	↑[lower-alpha 9]	home[lower-alpha 10]	sol[lower-alpha 11]	ceol[lower-alpha 12]	ceof[lower-alpha 13]
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	↑	↓	←	→	_ 005F
6_ 96		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	± 00B1
8_ 128	NBSP 00A0	1FB00	1FB01	1FB02	1FB03	1FB04	1FB05	1FB06	1FB07	1FB08	1FB09	1FB0A	1FB0B	1FB0C	1FB0D	1FB0E
9_ 144	1FB0F	1FB10	1FB11	1FB12	1FB13	258C	1FB14	1FB15	1FB16	1FB17	1FB18	1FB19	1FB1A	1FB1B	1FB1C	1FB1D
A_ 160	1FB1E	1FB1F	1FB20	1FB21	1FB22	1FB23	1FB24	1FB25	1FB26	1FB27	2590	1FB28	1FB29	1FB2A	1FB2B	1FB2C
B_ 176	1FB2D	1FB2E	1FB2F	1FB30	1FB31	1FB32	1FB33	1FB34	1FB35	1FB36	1FB37	1FB38	1FB39	1FB3A	1FB3B	2588
C_ 192	[lower-alpha 14]	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab
D_ 208	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab
E_ 224	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab
F_ 240	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab	tab

  Letter   Number   Punctuation   Symbol   Other   Undefined

1. Backspace and erase current character
2. Cursor on
3. Cursor off
4. Toggles Katakana characters (Model III)
5. Converts to wide 32 column mode
6. Backspace ← Cursor
7. Advance → Cursor
8. Downward ↓ linefeed
9. Upward ↑ linefeed
10. Move cursor to (0,0), also turns off 32 column mode
11. Move to start of line
12. Erase to end of line
13. Erase to end of frame
14. 192 to 255 are "Space Compression Codes", tabs for 0 to 63 spaces

References

Citations

1. Fylstra, Dan (April 1978). "Radio Shack TRS-80: An Owner's Report" (PDF). BYTE. Boston, MA, USA: BYTE Publications Inc.: 49–59. Archived (PDF) from the original on 2017-07-29. Retrieved 2017-07-29.
2. Heiserman 1983, p. 15.
3. Goldklang, Ira (2015). "Graphic Tips & Tricks". Archived from the original on 2017-07-29. Retrieved 2017-07-29.
4. Wiels. "TeleText - Het Protocol" (in Dutch). Mosaic characters. Archived from the original on 2017-12-22. Retrieved 2017-12-21.
5. Crawford 2003, p. 202.
6. Level II Basic Manual. Tandy / Radio Shack. 1978. pp. C1/C2.
7. "TRSM1ICH.TXT", L2/19-025: Proposal to add characters from legacy computers and teletext to the UCS (PDF), 2019-01-04
8. Heiserman 1983, p. 243.

Sources

• Heiserman, David L. (1983). Computer art and animation for the TRS-80. Prentice-Hall. ISBN 978-0-131-64749-7.CS1 maint: ref=harv (link)
• Crawford, Chris (2003). Chris Crawford on Game Design. New Riders. ISBN 978-0-131-46099-7.CS1 maint: ref=harv (link)

Further reading

• Bettencourt, Rebecca G. (2017) [2015]. "The Ultimate TRS-80 Font". Kreative Korporation. Archived from the original on 2017-07-29. Retrieved 2017-07-29.