|Names||Return, Enter, Carriage Return|
0x0d, 0x0a (<CR>,<LF>),|
MacOS: 0x0d (<CR>)
Unix,Amiga: 0x0a (<LF>)
|USB||"Keyboard Return (ENTER)", page 7, id 40|
A keyboard's Return key (or Enter key on IBM-compatible PCs) does (1) enters a new line and moves the cursor to the start of that line or (2) flushes an input buffer to the host computer, or (3) executes a dialog box's or menu's selected (or main) function. To be specific, the label "Return" refers to (1) and "Enter" refers to (2) and (3) but those functions are often overloaded on the same key with the meaning depending on the context.
On Macintosh the Return key and the Enter key are traditionally two distinct keys. Some older IBM terminals also have this distinction.
Depending on the keyboard layout the return key has different shapes. The most common are:
The US-ANSI keyboard layout (ANSI-INCITS 154-1988) has a horizontal Return key with the \ key above it. It is often 2.25u wide.
The horizontal Return key is preferred by many touch-typists over the vertical variant because it's left edge is closer to the centre and therefore easier to reach with the right pinky.
ISO and JIS
The ISO standard (ISO/IEC 9995-2) mandates a vertical Return key spanning two rows. The Japanese JIS standard (JIS X 6002-1980) uses the same key as ISO.
It is often 1.25u wide. Some have a step or gap to the ']' key, but it is more common to be use that space for key surface, being 0.25u wider in the top row. This latter variation is sometimes called "J-shaped".
The ISO enter is also known as European enter as most European standard layouts are based on the ISO layout.
A "backwards-L shaped" (or just "L-shaped") Return key is the union of the ISO and ANSI Return keys. The key is often called Big-ass Enter because of its size, or Asian enter because it is found on many East Asian keyboards.
There have been studies that have shown it to be easier to hit accurately than the ISO and ANSI Return keys.
However, with the backwards-L shaped Return key, the '\' key has to be relocated, often at the expense of having a smaller backspace or right shift key.
Many vintage PC keyboards with otherwise ANSI and ISO layouts have large Enter keys, in particular Alps SKCL/SKCM series and Alps clone boards from Asia. It is sometimes used as a compromise to please both ANSI and ISO typists, but it has been speculated that the main reason for the key is often not ergonomics but to reduce costs by having a more unified construction.
The stabiliser arrangement varies, even among keyboard with the same switches. There is often only one wire-stabiliser that is either vertical or horizontal, with the other bit stabilised with a slider or a dummy switch. Alps keyboards sometimes have a long horizontal (ANSI-style) stabiliser and one very short vertical. Very rarely do horizontal and vertical stabilisers overlap.
Another variant is to have a vertical Return key in the lower-right corner, to the right of the right Shift key. This variant is often merged with an ANSI-style shape, shaped like a Backwards L-shaped Return key but with the vertical portion spanning downwards instead of upwards.
There is often no key in front of the key's lower edge, allowing the vertical portion to be struck with less accuracy, perhaps using the side of the hand instead of a single finger. On some keyboards with this shape, the Return key is also higher than others.
ISO Enter and 2u Backspace
The earliest known Return key was the Line key on Donald Murray's tape-puncher (1901) which produced a distinct code on paper tape to be input into a Baudot-style telegraph. Murray intended to make telegraphing more like typing by using QWERTY keyboards instead of 5-key chord keyboards like Baudot's system. The Line key was located to the left of a small Space key.
The Blickensderfer Electric, also announced in 1901 had an electric return key: circular with a large 'L', located to the right of the home row and slightly up. Typewriters would be produced both in Blickenserfer's DHIATENSOR layout as well as in QWERTY. After extensive marketing, the typewriter was eventually (probably) not introduced onto the market because of its high price and because electric voltage was not yet fully standardized.
In 1929, the Electromatic typewriter was introduced with a key labelled Carriage Return. The key was circular, located in the same position as the Blickensderfer's: to the right of 'P' and one half row down. Electromatic Typewriters Inc was bought by IBM in 1933 becoming its typewriter division. Later IBM Electric typewriters kept the key in the same position but it grew larger and rectangular, thus spanning two rows. The legend was shortened to Return in the US. In non-English language markets, a large outline right-arrow symbol was used instead, referring to the movement of the carriage.
Smith Corona released their first typewriter with powered carriage in 1960 with a key in the same position with a right-arrow and the wording Power Return.
The first generation of IBM Selectric typewriters in 1961 had a similar keyboard layout as its predecessors but non-English keyboards now used a left-arrow symbol, now instead referring to the movement of the type-ball. Later Selectrics had varying different key layouts and introduced the familiar ↵ symbol.
Meanwhile as typewriters evolved, the Teletype Corporation extended its Murray telegraph code with different codes - and keys - for carriage movement (<CR> - "Carriage Return") and feeding a new line (<LF> - "Line Feed"), presumably to simplify the page printer in the receiving end. Teletype equipment were used for input and output on early computers and this segregated convention was later inherited by the character sets EBCDIC and ASCII. Some electronic keyboards, especially those that produce ASCII directly, had separate Return and Line Feed keys. Many cheaper electric keyboards had short horizontal Return keys because those did not require any stabilisers. Most systems these days use a single <LF> as end-of-line code in text encoding, except for Microsoft Windows PCs that still use <CR><LF> as the convention. Many Windows programs will produce a single <LF> if the Enter key is pressed with a modifier.
As computers keyboards and electric typewriters evolved, the number of keys increased and the physical layouts were standardized as the ISO, ANSI and JIS layouts. The now-standard keys are moved/shrunk versions of the classic IBM/Electromatic Return key: The ANSI key is moved one step right and halved in height and the ISO/JIS key is moved two steps to the right.
- oz.Typewriter: New Zealand’s Donald Murray: The Father of the Remote Typewriter. Retrieved 2016-08-27
- oz.Typewriter: Future Shock: How Blickensderfer Developed his Electric Typewriter. Retrieved 2016-10-13
- Remington and the Electromatic. Retrieved 2016-08-28
- The National Museum of American History: Electromatic Typewriter. Retrieved 2016-08-28