The Miscellaneous Technical block — U+2300 through U+23FF, 256 codepoints — holds the technical iconography of computing. Where Miscellaneous Symbols collects the pictograms of weather and astrology, this block collects the glyphs of keyboards, media remotes, electronics, and APL — the now-niche programming language whose strange operators were a major reason this block exists at all. Added in Unicode 1.1 (1993) and steadily expanded across versions through Unicode 13.0, the block now provides a stable, vendor-neutral way to typeset keyboard shortcuts, transport bar controls, and the universal power symbols defined in IEC 60417.
About this block
The Apple-style keyboard symbols are the most familiar inhabitants. ⌘ U+2318 PLACE OF INTEREST SIGN is the looped square Susan Kare drew for the 1984 Macintosh Command key, lifted from a road sign Steve Jobs spotted at a Swedish campground. ⌥ U+2325 OPTION KEY is the broken-bar glyph for the Option/Alt modifier. ⌃ U+2303 UP ARROWHEAD doubles as the Control-key marker on Apple keyboards. ⇧ Shift, while logically a keyboard-modifier symbol, technically lives in the Arrows block at U+21E7. ⎋ U+238B BROKEN CIRCLE WITH NORTHWEST ARROW is the Escape key; ⏎ U+23CE RETURN SYMBOL is the Return/Enter glyph; ⌫ U+232B ERASE TO THE LEFT is the backspace symbol; ⌦ U+2326 ERASE TO THE RIGHT is forward-delete. ⌨ U+2328 KEYBOARD itself is the icon for, well, a keyboard. The visual signs ⎇, ⎈, ⎌ at U+2387–U+238C are alternative modifier markers used on European and historic computer keyboards.
The IEC power symbols form a small but indispensable cluster. ⏻ U+23FB POWER SYMBOL is the standardised circle-with-vertical-line that appears on the power button of every laptop, monitor, and consumer electronic. ⏼ U+23FC POWER ON-OFF SYMBOL is the toggle variant; ⏽ U+23FD POWER ON SYMBOL the solid "on" variant; ⏾ U+23FE POWER SLEEP SYMBOL the crescent-moon "sleep" icon used on Apple keyboards. The matching "power off" glyph ⭘ U+2B58 CIRCLE actually lives in the adjacent Miscellaneous Symbols and Arrows block — a small piece of cross-block dependency to be aware of when typesetting hardware documentation.
Media transport controls were added in Unicode 6.0 (2010) to give podcast apps, video players, and remote-control buttons a vendor-neutral set of glyphs. ⏵ U+23F5 PLAY, ⏸ U+23F8 PAUSE, ⏹ U+23F9 STOP, ⏺ U+23FA RECORD, ⏯ U+23EF PLAY OR PAUSE, ⏮ U+23EE SKIP TO START, ⏭ U+23ED SKIP TO END, ⏪ U+23EA FAST REVERSE, ⏩ U+23E9 FAST FORWARD, ⏫ U+23EB FAST UP, ⏬ U+23EC FAST DOWN. The hourglass pair ⌛ U+231B HOURGLASS and ⏳ U+23F3 HOURGLASS WITH FLOWING SAND are the "loading" and "waiting" indicators that became emoji in Unicode 6.0. ⌚ U+231A WATCH provides a generic wristwatch icon.
The block also holds mathematical and structural typography that is too specialised for the Mathematical Operators block. ⌈ U+2308 LEFT CEILING, ⌉ U+2309 RIGHT CEILING, ⌊ U+230A LEFT FLOOR, and ⌋ U+230B RIGHT FLOOR are the floor and ceiling brackets used in mathematics for rounding. ⌜ ⌝ ⌞ ⌟ at U+231C–U+231F are the corner brackets used as a compact alternative. ⌬ U+232C BENZENE RING is the chemistry symbol for benzene. ⌶ U+2336 APL FUNCTIONAL SYMBOL I-BEAM opens a long sequence of APL functional symbols at U+2336–U+237A that exists primarily to allow legacy APL source code to round-trip through Unicode.
A few practical typographic odds and ends round out the block. ␣ U+2423 OPEN BOX is the printable shorthand for a space character; ⌧ U+2327 X IN A RECTANGLE BOX is the "Erase" key on older terminals; ⎯ U+23AF HORIZONTAL LINE EXTENSION and the matching brace pieces ⎛ ⎜ ⎝ ⎞ ⎟ ⎠ at U+239B–U+23A0 let typesetters build large multi-line braces and parentheses out of separate glyph parts, a holdover from the days before true scalable typography.