HP 110 / HP Portable and HP 110 Plus / HP Portable Plus, where in a modified version of the character set box-drawing characters were added in reserved areas of their normal HP Roman-8 character set. Unix, CP/M, BBS On many Unix systems and early dial-up bulletin board systems the only common standard for box-drawing characters was the VT100 alternate character set (see also: DEC Special Graphics). The escape sequence Esc ( 0 switched the codes for lower-case ASCII letters to draw this set, and the sequence Esc ( B switched back: On some terminals, these characters are not available at all, and the complexity of the escape sequences discouraged their use, so often only ASCII characters that approximate box-drawing characters are used, such as - (hyphen-minus), | (vertical bar), _(underscore), =(equal sign) and + (plus sign) in a kind of ASCII art fashion. Modern Unix terminal emulators use Unicode and thus have access to the line-drawing characters listed above. Historical Many microcomputers of the 1970s and 1980s had their own proprietary character sets, which also included box-drawing characters. Some of these sets, such as Commodore's PETSCII, include box-drawing symbols with no corresponding Unicode character. Sinclair The Sinclair ZX80, ZX81 and Spectrum included a set of text semigraphics with block elements and dithering patterns in the ZX80 character set. BBC and Acorn The BBC Micro could utilize the Teletext 7-bit character set, which had 128 box-drawing characters, whose code points were shared with the regular alphanumeric and punctuation characters. Control characters were used to switch between regular text and box drawing. Teletext G1 Block Mosaics Set: The BBC Master and later Acorn computers have the soft font by default defined with line drawing characters. Amstrad The Amstrad CPC character set also has soft characters defined by default as block and line drawing characters. The CP/M Plus character set used on various Amstrad computers of the CPC, PCW and Spectrum families included a rich set of line-drawing characters as well: Apple MouseText is a set of display characters for the Apple IIc, IIe, and IIGS that includes box-drawing characters. Teletext The World System Teletext (WST) uses pixel-drawing characters for some graphics. A character cell is divided in 2×3 regions, and 26 = 64 code positions are allocated for all possible combinations of pixels. These characters were added to the Unicode standard in Version 13. Others Some recent embedded systems also use