Editing Tektronix 4010 (section)

===Graphics input===
For graphics input, the terminal used a pair of thumb wheels on the [[alphanumeric keyboard|keyboard]] to control the position of a [[cursor (user interface)|cursor]]. The cursor was displayed using a lower intensity of the electron beam that had insufficient energy to cause the storage system to trigger. The cursor was dynamically refreshed by the electronics of the terminal. The cursor was turned on with {{keypress|ESC}} ({{keypress|Control|Shift|K}}) (which also turned off graphic mode if it was on), and then {{keypress|SUB}}  ({{keypress|Control|Z}}). The position was sent back to the computer using the same X,Y encoding as the graphics commands. This could be done interactively by sending the {{keypress|ESC|SUB}} and then pressing a key on the keyboard, or immediately by the host sending {{keypress|ESC|ENQ}}.{{sfn|Tektronix|1974|pp=1-7, 1-8}}