Many of the non-alphanumeric characters were positioned to correspond to their shifted position on typewriters; an important subtlety is that these were based on mechanical typewriters, not electric typewriters. Mechanical typewriters followed the standard set by the Remington No. 2 (1878), the first typewriter with a shift key, and the shifted values of 23456789- were "#$%_&'() –  early typewriters omitted 0 and 1, using O (capital letter o) and l (lowercase letter L) instead, but 1! and 0) pairs became standard once 0 and 1 became common. Thus, in ASCII !"#$% were placed in second column, rows 1–5, corresponding to the digits 1–5 in the adjacent column. The parentheses could not correspond to 9 and 0, however, because the place corresponding to 0 was taken by the space character. This was accommodated by removing _ (underscore) from 6 and shifting the remaining characters left, which corresponded to many European typewriters that placed the parentheses with 8 and 9. This discrepancy from typewriters led to bit-paired keyboards, notably the Teletype Model 33, which used the left-shifted layout corresponding to ASCII, not to traditional mechanical typewriters. Electric typewriters, notably the more recently introduced IBM Selectric (1961), used a somewhat different layout that has become standard on computers—​​following the IBM PC (1981), especially Model M (1984)—​​and thus shift values for symbols on modern keyboards do not correspond as closely to the ASCII table as earlier keyboards did. The /? pair also dates to the No. 2, and the ,< .> pairs were used on some keyboards (others, including the No. 2, did not shift , (comma) or . (full stop) so they could be used in uppercase without unshifting). However, ASCII split the ;: pair (dating to No. 2), and rearranged mathematical symbols (varied conventions, commonly -* =+) to :* ;+ -=.
Many of the non - alphanumeric characters were positioned to correspond to their shifted position on typewriters ; an important subtlety is that these were based on mechanical typewriters , not electric typewriters . Mechanical typewriters followed the standard set by the Remington No . 2 ( 1878 ) , the first typewriter with a shift key , and the shifted values of 23456789- were " # $ % _ & ' ( ) – early typewriters omitted 0 and 1 , using O ( capital letter o ) and l ( lowercase letter L ) instead , but 1 ! and 0 ) pairs became standard once 0 and 1 became common . Thus , in ASCII ! " # $ % were placed in second column , rows 1–5 , corresponding to the digits 1–5 in the adjacent column . The parentheses could not correspond to 9 and 0 , however , because the place corresponding to 0 was taken by the space character . This was accommodated by removing _ ( underscore ) from 6 and shifting the remaining characters left , which corresponded to many European typewriters that placed the parentheses with 8 and 9 . This discrepancy from typewriters led to bit - paired keyboards , notably the Teletype Model 33 , which used the left - shifted layout corresponding to ASCII , not to traditional mechanical typewriters . Electric typewriters , notably the more recently introduced IBM Selectric ( 1961 ) , used a somewhat different layout that has become standard on computers—​​following the IBM PC ( 1981 ) , especially Model M ( 1984)—​​and thus shift values for symbols on modern keyboards do not correspond as closely to the ASCII table as earlier keyboards did . The / ? pair also dates to the No . 2 , and the , < . > pairs were used on some keyboards ( others , including the No . 2 , did not shift , ( comma ) or . ( full stop ) so they could be used in uppercase without unshifting ) . However , ASCII split the ; : pair ( dating to No . 2 ) , and rearranged mathematical symbols ( varied conventions , commonly - * = + ) to :* ; + -=.
What were used instead of 0 and 1?
What were used instead of 0 and 1 ?
using O (capital letter o) and l (lowercase letter L) instead
using O (capital letter o) and l (lowercase letter L) instead