Editing Typewriter (section)

==== Tab key ====
{{Main|Tab key}}

To facilitate typewriter use in business settings, a tab (tabulator) key was added in the late 19th century. Before using the key, the operator had to set mechanical "tab stops" (pre-designated locations to which the carriage would advance when the tab key was pressed). This facilitated the typing of columns of numbers, freeing the operator from the need to manually position the carriage. The first models had one tab stop and one tab key; later ones allowed as many stops as desired, and sometimes had multiple tab keys, each of which moved the carriage a different number of spaces ahead of the decimal point (the tab stop), to facilitate the typing of columns with numbers of different length ($1.00, $10.00, $100.00, etc.) such that the decimal points were vertically aligned. Typically, tab stops could be set by a key-set tabulator control (either by a lever or keys on the keyboard—usually labelled with "+" or "-", or "set" and "clear") or moveable tab stops at the back of the machine, similar to margin stops.