The Apple ][ and TTYs and other old computers had "bit pairing keyboards", where the punctuation marks above the digits were aligned with the ASCII values of the corresponding digits, different by one bit.
>A bit-paired keyboard is a keyboard where the layout of shifted keys corresponds to columns in the ASCII (1963) table, archetypally the Teletype Model 33 (1963) keyboard. This was later contrasted with a typewriter-paired keyboard, where the layout of shifted keys corresponds to electric typewriter layouts, notably the IBM Selectric (1961). The difference is most visible in the digits row (top row): compared with mechanical typewriters, bit-paired keyboards remove the _ character from 6 and shift the remaining &() from 7890 to 6789, while typewriter-paired keyboards replace 3 characters: ⇧ Shift+2 from " to @ ⇧ Shift+6 from _ to ^ and ⇧ Shift+8 from ' to . An important subtlety is that ASCII was based on mechanical typewriters, but electric typewriters became popular during the same period that ASCII was adopted, and made their own changes to layout.[1] Thus differences between bit-paired and (electric) typewriter-paired keyboards are due to the differences of both of these from earlier mechanical typewriters.
>[...] Bit-paired keyboard layouts survive today only in the standard Japanese keyboard layout, which has all shifted values of digits in the bit-paired layout.
>[...] For this reason, among others (such as ease of collation), the ASCII standard strove to organize the code points so that shifting could be implemented by simply toggling a bit. This is most conspicuous in uppercase and lowercase characters: uppercase characters are in columns 4 (100) and 5 (101), while the corresponding lowercase characters are in columns 6 (110) and 7 (111), requiring only toggling the 6th bit (2nd high bit) to switch case; as there are only 26 letters, the remaining 6 points in each column were occupied by symbols or, in one case, a control character (DEL, in 127).
>[...] In the US, bit-paired keyboards continued to be used into the 1970s, including on electronic keyboards like the HP 2640 terminal (1975) and the first model Apple II computer (1977).
>A bit-paired keyboard is a keyboard where the layout of shifted keys corresponds to columns in the ASCII (1963) table, archetypally the Teletype Model 33 (1963) keyboard. This was later contrasted with a typewriter-paired keyboard, where the layout of shifted keys corresponds to electric typewriter layouts, notably the IBM Selectric (1961). The difference is most visible in the digits row (top row): compared with mechanical typewriters, bit-paired keyboards remove the _ character from 6 and shift the remaining &() from 7890 to 6789, while typewriter-paired keyboards replace 3 characters: ⇧ Shift+2 from " to @ ⇧ Shift+6 from _ to ^ and ⇧ Shift+8 from ' to . An important subtlety is that ASCII was based on mechanical typewriters, but electric typewriters became popular during the same period that ASCII was adopted, and made their own changes to layout.[1] Thus differences between bit-paired and (electric) typewriter-paired keyboards are due to the differences of both of these from earlier mechanical typewriters.
>[...] Bit-paired keyboard layouts survive today only in the standard Japanese keyboard layout, which has all shifted values of digits in the bit-paired layout.
>[...] For this reason, among others (such as ease of collation), the ASCII standard strove to organize the code points so that shifting could be implemented by simply toggling a bit. This is most conspicuous in uppercase and lowercase characters: uppercase characters are in columns 4 (100) and 5 (101), while the corresponding lowercase characters are in columns 6 (110) and 7 (111), requiring only toggling the 6th bit (2nd high bit) to switch case; as there are only 26 letters, the remaining 6 points in each column were occupied by symbols or, in one case, a control character (DEL, in 127).
>[...] In the US, bit-paired keyboards continued to be used into the 1970s, including on electronic keyboards like the HP 2640 terminal (1975) and the first model Apple II computer (1977).